"Backdoor?" you repeat, inadvertantly answering him.

Shocked by his appearance, and more than a little distracted by his finger running along your desperately eager slit, you try in vain to pay attention to his words, catching only a few.

"Backdoor?" you repeat.

"Hell yeah, I love making you squeal on my cock. That ass was made for fucking," he says, rubbing up against your butt.

In an excited trance you push back against him. "Fuck my ass," you tell him, thinking of him fucking you doggy-style. You're not sure why he takes the soap from you, but you occupy yourself with tugging on your rubbery nipples as he lines himself up. To help you arch your back, pushing your butt toward him.

At first he runs the soap up and down your ass crack, the suds from it drawn downward by gravity and the endless cascade of hot water. When he runs his amazing cock up and down your crack you moan, anticipating that monster impaling your pussy.

It's entirely a surprise when instead he presses the giant knob of it against the puckered rim of your anus instead.

"H... Oh!" you exclaim, meaning to protest but startled by his sudden entry.

"Ho, huh? You want to be treated like a dirty little whore?" he asks with a chuckle in your ear. "Hard and fast, then."

You open your mouth to protest in spite of the burning of his thick cock thrusting inwards. A harder thrust steals the words you might have said, making you squeal at the pain of a dick twice as large as your own going up your ass. Only the knowledge that it's actually your sister's ass and that she's done this often makes it bearable. In fact, it seems to make it almost pleasurable.

The more he thumps in and out of you the less it seems to hurt, and the more pleasurable it seems to become. It seems as if not all of the wet liquid dripping down to the drain is water as you find yourself mewling when he pulls out and stops.

"Come on now Sue. It's no fun if you're not doing something. Fight me, fuck me, encourage me, tell me what a filthy little whore you are. I might just get some ideas, maybe do that thing you've been refusing to let me do if you don't participate more."

You feel so confused. You're a guy, but you've just been ass-fucked and at the end it was feeling good! Now he wants you to beg for it? No, not quite. Not you, he wants your sister Sue to act.