"EEEEEEEEEEEEEEEEEEE!" Susan shrieked. Her face flushed bright red as she climaxed. Her vaginal muscles began to pulse around Debbie's hand. To try and increase Susan's pleasure, Debbie leaned forward and began to lick Susan's clit while moving her hand around in Susan's vagina. Susan responded by clamping her legs on either side of Debbie's head, trapping her mouth on her clit.

Susan was reduced to making inarticulate noises in the back of her throat. She thrashed her arms around, and just missed knocking over the lamp on the table behind the couch. Susan's hips began to buck, and Debbie hung on for the ride, sucking and tonguing Susan's clit.

Susan's orgasm went on and on. Gradually, if occurred to Debbie that she should stop stimulating Susan's clit unless she wanted the girl to come all night. A few minutes after she stopped sucking it, Susan began to subside. Soon, she had regained the power of speech.

"Holy Shit! That was AWESOME! Oh, that was totally FANTASTIC!"

"Why thank you." Debbie said, humbly. "Did I do it right?"

Susan sat up and took Debbie's head in both hands and kissed her hard. "You did it perfectly!" she said softly, her lips still touching Debbie's. Then she kissed her again, deeply and passionately and hugged Debbie to her, breast to breast, as her orgasm slowly faded. Debbie stroked her friend lovingly as she recovered.

Susan eventually released her grip and sat back, breathing deeply to clear her head. The two sat there looking at each other, their arms and legs still intertwined. Their eyes roved over each other's bodies as if seeing them for the first time.

Susan broke the silence. "We were interrupted. Do you still want to see what it would be like to stretch your pussy?"

Debbie nodded eagerly. "Yes, I think I would like to try. What do I do first?"

"Let's see you," Susan said, gently pulling Debbie's pussy open again. She put two fingers into Debbie and moved them around testing Debbie's flexibility. Debbie leaned back on her elbows, trying to relax her pussy. Susan stroked her fingers in and out of Debbie, picking up lubrication and tugging every which way in Debbie's opening.

"Now you're getting ME hot!" Debbie said, playfully.

"Turnabout is fair play, dear," Susan said, smiling. She continued to work Debbie's pussy. She put two fingers in on either side and started pulling Debbie open, tugging and stretching.

"You're looser than I was," Susan observed, "Gus must have a bigger cock. Or Mark does."

"Mark's cock is pretty big. It's bigger around than Gus', but Gus' is much longer, and goes much deeper. He also has many times the stamina that Mark does. He just goes and goes and goes. Gus fucks me three or four times a day. Every time he makes me cum over and over. The best thing is - he's in complete control. He knows he owns my pussy and he takes it whenever he wants. I have no say-so at all. I have to be ready anytime of the day or night. Being a dog's bitch is the most intensely erotic thing I have ever done. It's so primal, surrendering your body to an animal. I would not give it up for anything. Oooo! Talking about this is making me really wet. "

Susan was getting rougher with Debbie's pussy. She was pulling harder and harder. Debbie thought it felt wonderful. She was looking forward to being able to tie with Gus.

"You may not need the bottles and stuff I did," Susan said. "You're coming along nicely."

"Let me see!" Debbie sat up and looked at herself. Her opening had been stretched to almost three inches wide. She could easily see the bottom of her vagina through the hole.

"See? It's just a matter of trying." Susan said looking at Debbie's enlarged opening. "I bet you could get it bigger than mine with no trouble at all."

"Let me try," Debbie said, taking matters into her own hands. She stuck two fingers of each hand into her pussy, spread her legs as far as possible and started pulling on herself as hard as she could. She strained and pulled and tugged. She made the worst faces while she was trying to pull herself open. Soon, she was able to get three fingers of each hand in her hole. She pulled even harder then. Soon, she was almost exhausted from the effort. "Now let's see", she said, sitting up.

Susan and Debbie examined Debbie's pussy.

"Wow!" Susan said. "I thought you were flexible, but this is better than I ever did!"

Debbie looked down at her opening and then over at Susan's. She was clearly bigger than Susan. Her pussy gaped open at least four inches.

"Let's see how big it is," Susan said, and jumped up and ran to the kitchen, coming back with a soda can in her hand. "Spread wide, now."

Debbie watched in fascination as Susan slid the can of soda into her with only slight resistance. When Susan took her hand away, the can stuck halfway out of Debbie's pussy. Debbie reached down and pushed on the bottom of the can. Slowly she forced in into her until it disappeared completely and her vagina closed behind it.

"I'm impressed!" Susan said. "Can you stand up?"

Debbie got to her feet with some hesitation. She stood up carefully and walked around the room. "No problem," she said. "I can feel it in me. It feels REALLY good! Especially when I walk. I can feel it moving around inside me. It's like having a big cock in you and still being able to move around." She giggled, and then admitted, "This is nice. I could get used to this."

"Can you get it out?' Susan asked with a concerned tone. Debbie lay down on the couch with her ass hanging over the edge of the cushions. She tightened her abdomen and relaxed her vaginal muscles. When she felt the can shift; she tightened her vaginal muscles and the can slowly reappeared in her opening. A look of concentration came over her face. As she worked to contract and relax the right sequence of abdominal and vaginal muscles, the soda can slowly slid back out again and dropped in to Susan's waiting hand.

"That's one talented pussy you have there!" Susan said, waving the can. "Would you like a drink?"

"It may be a little too warm, now" Debbie laughed. "That's a good exercise. I could feel myself using different muscles. When I concentrated, I could control them separately to move the can around." Debbie thought for a moment and said, "You know, I was worried that stretching myself out so I could take Gus' knot would leave me too loose for regular fucking. Mark would be sure to notice if I were the size of the Alaskan Pipeline, but if I exercise, I bet I can squeeze down smaller than I was before! Watch me try." Debbie spread her legs so Susan would have a good view, then she tried to contract specific muscles in her pussy. After a few second, she found the right combination and her gaping opening began to get smaller.

"It's working!" Susan told her. "Keep going. That's it!"

Encouraged by her success, Debbie tried again. Her opening got larger and then smaller again as she found the right muscles groups to use. Finally, she said. "I think I have it. Now watch this!"

Susan's mouth dropped open in delighted amazement as Debbie's opening got smaller and smaller. Soon, it closed completely. Susan rubbed her hand over Debbie's pussy and tried to slip a finger inside her. Her eyebrows shot up and she said, "Wow! You're like a virgin. I've GOT to learn to do this."

At that moment, the two dogs came trotting into the room, having finished their playtime in the yard. Both dogs flared their nostrils and sniffed at the heavy odor of sex in the air, each dog then wanted to check his bitch. Debbie and Susan immediately jumped to their feet, grabbed their dimpled behinds with both hands, spread their legs, and presented their pussies to their studs. The dogs sniffed and licked them, and then nudged them to the floor. Both girls happily assumed the breeding position and were mounted immediately.

Debbie and Susan managed to take positions facing each other so they could watch each other being serviced. When they were together, the dogs would usually both want to fuck at the same time. The girls found that this increased their pleasure several ways, in having someone to watch, in being watched, and because they got fucked more often. The dogs seemed to compete with each other as to who could give his bitch the most cock.

After climaxing twice, Debbie decided that this was the time to try to tie with Gus. She was loose, she was lubricated, and she was hot as hell. She lowered her head to the floor and braced her hands on the leg of the couch. She spread her legs wide and started pushing back on Gus' cock, working her hips to try to get his knot into her. Gus seemed to sense what she wanted, and he stopped stroking and began to push steadily. Debbie tried so hard to get Gus' knot into her that, as she pushed, her labia and her clit disappeared inside her body.

Slowly, Debbie's enlarged pussy stretched wider and wider, while the huge knot slid into her. Finally, it popped in. Her opening had been so strained from the effort that it clamped down hard on the base of Gus' cock, locking his knot inside her as nature intended. As soon as they were tied, Gus came, spraying the deepest part of Debbie's vagina with bolt after bolt of his steaming cum. As soon as his cock started to pulse inside her, Debbie came harder than she ever had. She screamed at the top of her lungs at the incredibly intense pleasure she was feeling. Her orgasm went on and on, longer than any other because of the stimulation from being tied to her stud. When she came down enough to be aware of her surroundings again, she looked over at Susan, who was also still on all fours, tied with Max.

"Isn't it wonderful?" Susan asked.

"It's incredible! I've never felt anything like this. It's like I've become a part of him. Like my pussy and his cock have merged together. I can feel his heartbeat through his cock. Oh, thank you for teaching me about this!" Debbie leaned forward to Susan and kissed her passionately on the mouth. Susan responded enthusiastically and they began using their tongues to explore each other's mouth. Susan balanced on her knees and one hand to use her free hand to caress Debbie's breasts as they hung swaying from her chest. Soon, both girls were lost in their own world. Neither of them noticed when the front door swung open and Mark stepped into the room, his suitcase in hand and garment bag over his shoulder.

"I'm sorry." Mark said, clearing his throat. "I should have called first."

Debbie and Susan broke their passionate kiss, but otherwise just froze into place, Susan holding Debbie's breast in mid-caress, both on the floor with their stud-dog's cocks still locked in their cunts.

"I'll just put the bags in the bedroom," Mark said. He walked off down the hall, leaving the two girls to stare at each other, their eyes wide with surprise. Neither could think of anything to say, and neither could do anything, since they were quite effectively trapped where they were.

Mark returned a couple of minutes later. He sat down in his recliner, crossed his legs and studied the tableau before him. Two beautiful girls, one a blonde teen he had not met, the other his lovely wife; both on all fours on the living room carpet, naked, except for the dog collars around their necks, both with large dogs on top of them with their huge cocks stuck in their cunts. From their disheveled state, he figured that they had both just been seriously fucked by the dogs and were still in the throes of afterglow from their orgasms. This was about the most erotic thing Mark had ever seen, but he concentrated on keeping a straight face, his crossed legs hiding his growing erection.

"Mark..." Debbie began to say something, but ran down as soon as she opened her mouth. She could not think of anything to say. This was one situation that could not be explained away.

Mark looked at Debbie as if expecting her to continue. He was disappointed. He really wanted to hear her try to explain the situation as anything other than what it was. When she did not continue, he looked at the other girl. She was a stunning blonde with nice breasts and a tight ass. The fact that she was presently attached to a dog in no way diminished her beauty. Mark realized that he was looking forward to the story of how these two girls had met.

"Hi," Mark said to Susan. "I'm Mark, Debbie's husband. I don't think we've met. I'm sure I would remember you." Mark reached out to Susan, who leaned heavily on her left arm so she could pick her right up off the floor and shake hands.

"Ah, I'm Susan. Debbie has told me so much about you, I feel like I know you already." Susan flushed. Having such a normal conversation from this position was the last thing she ever expected to be doing.

"And this is... ?" Mark indicated Susan's sexual partner with a small wave of his hand.

"Oh! This is Max." Susan wanted to say more about Max, but everything that could be said seemed kind of superfluous at the moment.

Mark reached past Susan's head and patted Max and briefly scratched his ears. Max wagged his tail vigorously in response.

Susan said, "Ooooooooo!" as the motion of Max's wagging was transmitted through their connection to her pussy.

Mark withdrew his hand and said, "Sorry, Max. We'll get better acquainted later. You seem a little..." Mark wanted badly to say 'tied up', but he resisted the urge, "... busy at the moment."

Gus saw Max get his ears scratched and nothing would do but that he got the same treatment, with the same end result on Debbie, who reflected that she could be enjoying this under different circumstances.

After Gus settled down, Mark turned to Debbie, "How are you doing today, darling? Have a busy day?" His poker face was beginning to crack. He could not keep this up much longer.

Debbie had been staring at her husband in stark amazement ever since he had come back into the room. Whatever she expected, whatever she thought about how this might go, this was really not it. When he asked her about her day, she saw the muscles along his jaw twitch and realized it was all a fraud.

"You bastard!" Debbie practically shouted with relief. "You knew! Dammit, you're enjoying this!" Her voice began to quaver with the release of tension in the room.

Mark could not manage to keep up the pose any longer. He cracked a huge smile and started laughing. Both girls followed suit, laughing so hard their breasts shook. Mark found that he needed to adjust his erection to a more comfortable position after seeing that.

"Yes, dear. I've known ever since my first night back from my first trip. There were so many little things that happened that day that I became suspicious. You and Gus kept having little moments together. Then, when you were in the kitchen fixing dinner, I started to peek in on you to see if you needed any help. I had just cracked the door when I saw you do your 'brace for inspection' for Gus. Damn, but that was the hottest thing I had ever seen. At least it was until later that night. I woke up when you got out of bed and I followed you out to the garage. I watched you and Gus through the window in the garage door. I saw the whole thing from beginning to end. Then I went back to the house and was about to go back to the bedroom when I saw you stop to enjoy the night breeze. After seeing how happy you were with Gus, and seeing you stand there in the moonlight, glowing in the night like a goddess, there was no way I could be mad at you. You may not realize it, but you have changed. There are many things that are different, but it comes down to the fact that you are happier now than I have ever seen you before. There was no way I could ever think of spoiling that, so I decided to keep quiet about what I knew. I was going to wait until you were ready to tell me what was going on. I went back to bed and pretended to be asleep, but watching you in the garage had made me so horny that I had to have you, even knowing that I would be getting sloppy seconds after Gus.

Ever since then, I have tried to make it easy for you and Gus to be alone when you needed to. I always listened before I walked into rooms, and I tried to make as much noise as possible so you would know where I was. I should have checked before coming in the door tonight, but I was tired from the trip and I walked in without thinking. I'm sorry I played my little joke on you. When I saw the two of you together, looking at me like deer in the headlights, I just could not resist. Please forgive me."

On hearing this, Debbie was close to tears. Susan was choking up, too. Debbie sniffed back her tears and said, "What did I ever do to deserve a wonderful husband like you?"

Susan said, "Mark? I have to ask. Are there any more out there like you? I sure hope so."

Later that night, when Mark, Debbie, and Susan were lying in bed together with the dogs curled up at the foot of the bed, Debbie and Susan told Mark all about how they met. Their story made Mark hard again and this time it was Gus and Max who got sloppy-seconds.