You take too long to choose

You lay slowly processing her words through your sex-addled haze, despite your pussy's best efforts to distract you, you manage to consider the options. But you were afraid of how much it could hurt if she took your ass, but she was too big for you to give oral without gagging, plus the thought of sucking a cock didn't thrill you, despite your own body disagreeing. You also had to consider that if you didn't satisfy her she might give you another punishment on top, and also-

-"Well if you aren't going to choose, then I pick your cunt"

"W-what?" you gasp

"You were taking too long." she says nonchalantly as she presses her cock against your pussy

You panic. "Wait! I choose-"

"Too late!" she says, thrusting in

"N-noooo...." your protest trails off into a moan as you feel her cock part your walls. You instinctively clamp down on her as she enters, but this only serves to intensify the pleasure of her agonizingly slow entrance. As her cock advances she leans forward presses her lips against yours. You open your mouth in surprise and feel your own sisters tongue mingle with yours. You still feel her cock inching in as she French kisses you, and, overwhelmed by the sensations from your upper and lower mouth, you cum hard. Gwen hilts herself inside you fully, the tip of her shaft just barely kissing your cervix as she assaults your mouth. As your orgasm finally subsides, she pulls out her cock and tongue, giving a lewd smile.

"Cumming on the first stroke? Did you miss being fucked by me that much?" She slides her cock all the way back in and is soon fucking you earnestly in a full mating press.

Between the orgasm and recovering your breath from the kiss, it was impossible to answer right away. You lay there panting helplessly until an impatient Gwen gets your attention by squeezing and pulling your nipples painfully

"I asked you a question, you slutty bitch, you better listen to your big sister!"

"Y-yes..!" you blurt out, still out of breath. You didn't mean to say yes, but you know it was true.

"Good girl..." she doesn't let go of your nipples, instead massaging the pain away. Every time she pulled or rolled them, you felt a twitch in your cervix.

"Don't you wanna see these things grow and swell? She finally let go of your nipples, instead cupping your breasts gently, even as she fucked you not-so-gently. "I'm sure you'd make so much milk. I'd finish what the baby couldn't and milk you dry every night.."

"St-stop..." you plead. The thought of your breasts swelling and leaking milk as you get pregnant, with Gwen drinking from them is almost enough to make you reconsider your desire to turn back into a guy.

"You know..." she continues, going back up to your nipples. "They say that massaging the nipples helps stimulate contractions during childbirth.." she gently rolls your rock hard nipples between her thumb and forefinger. You screw your eyes shut and futilely try to shut out her voice. She leans in and whispers "If I cum inside you I can tease you like this when you give birth..."

The image of Gwen massaging your swollen breasts as your water breaks is enough to make you cum. She pins you under her, kissing you silent as you squirm and writhe and squirt all over her cock. If she cums inside me, she can fuck me like this every day forever... You feel her cock grow even harder and spasm, and realise she's going to cum too.