The wife bot keeps her promise.

"If you think you are going to get out of this one, you are wrong!"
As Abby pulls out, the wife has her cock plugging your hole. She can't reach you, so she pushes forward, leaning into her cock. Oh gosh this one is bigger around. Abby is trying her best to stay out of the way, but with her and the wife bot and now your belly...it's getting crowded in here. You can't move without bumping into someone.
"Stop resisting! Your ass won't be able to after having Abby in there, so don't waste my time."
You try really hard to loosen your butt for her. She makes a little headway, and that's all she needs. She forces your cheeks apart as she burrows into you. You can feel the length sliding along your cheeks before entering you. You feel the familiar sensation of cock snaking through your insides. You feel balls press against your legs, so you lift up to kneel on them, and breasts slide onto your back until you are sandwiched between the wife bot's balls and tits, her crotch pressed into your ass.
"Daddy, are you going to be okay?"
"Oh he can take a lot. On our honeymoon I pumped him up so big I slept on his belly like a waterbed."
"Daddy!"
Well you don't know how it works, but it does. Apparently it works quite well, if what she said is true. You feel her cum surging into you. You could swear you feel the hum of a pump below you in her balls.
"Abby go get Daddy something sexy to wear."
"Yes, Mom..." Abby squeezes by the wife with some effort. She pokes her head out the door to see if anyone is around, then wobbles off.
"Hey--eep! Sorry!" You see a sister bit standing there, shocked yet not going away. Abby left the door open.
"Katie? What are you doing?" Abby says as she waddles back.
"They are having sex in there Abby, don't look." Katie covers Abby's eyes.
Katie looks to be a base model, at least from where you are. Abby shooes the sister bot away and tosses the pile of clothes to the wife. In it is also a butt plug.
"What are you doing Sue?" Katie just named the wife bot.
"Well," she says as she pulls out and stuffs you with a plug the width of her cock's head, "Your brother enjoys incestuous girlcock. I want it to be obvious to everyone here, so you know how damaged he is in the head." She looks back at you.
"Bro, serious?" Her tone is seriously pissed off, but she winks at you with a smirk.
"Yes he is. Make sure he is dressed properly before you let him leave this bathroom," Sue says as she storms off. "Abby! We are going to have a talk!"
Abby waddles off.
"So you like incestuous girlcock, hmm?"
"Yes, Katie." You are still bent over, ass at the ready.
"Prove it, let me fuck you." You hear clothes rustling, then feel a hard cock resting against your ass, leaking wetness.
"Fuck me then."
She pushes in alongside the butt plug. Being a base model, Katie's cock is not taller than her or thicker than her thigh. It's still really big though. You can't relax your distended butt any more for her; she will have to **** her way in.
"I can't believe it...it fits!" Katie tells you after a huge push. "It's like my dick is submerged. All that cum in you, huh? I wish I had known you would fuck me long ago. Sure would have saved me all the effort masturbating. Jackie and Tilly had each other, lucky bitches. They were twins, of course they dumped their cum in each other. You shared a room with them, ever wonder why they always slept in the same bed? You yourself said they moved a lot in their sleep. Imagine their faces when they hear about this." She drones on as she fucks your butt. "I had first dibs. They are gonna be pissed at me! Hehe. Can I cum in you, pretty please? You'd be the best brother ever!"
"Yeah, you can. Bet I'm going to be getting more once I start walking around in that thong."
"Yeah, how's my cum?"
"Filling?"
"I don't really know what answer I expected. Oh, you need to tighten up," Katie says after she pulls out. "You got a leak."
"I can't close up, Katie, I'm too loose."
"Oh well, Sue is gonna be pissed. Here, step up," Katie assists you in pulling up your thong. Then a stretchy bodysuit. By the time she pulls it up your legs, it's soaked by your cum leak, making it see-through. The black high-riding thong is clearly visible, among other things.
You lift up, once the belly has inevitably drained a little...well a lot. You are only hanging to your knees when you try to right yourself again, and manage to do so with great effort.
"Well time to go face the crowd," you tell Katie while adjusting your thong so it doesn't hide the gigantic butt plug. You waddle out, unknowingly swaying your hips so well that Katie slaps your butt.