Slap her ass

You reel back and plant the palm of your hand squarely on Emily's ass, leaving a nice red welt there. Emily jumps, her back straightening even while you're still inside her.

"Again," she gasps.

"Spank her again," Jordan says, her fingers deep inside your older sister. "But make her beg for it."

You look down at your best friend, who's panting from the fucking and the spanking. "Please," she says. "Slap my ass again."

You do it again. Your hand flies through the air and slams down again on Emily's cheek, leaving an even angrier red mark. Emily shakes at your touch, groaning loudly.

"Keep fucking me," she says. "Fuck me as you slap me."

Jordan is looking like she's enjoying this. Kiera looks like she's in a trance, her eyes rolled back in her head as her roommate strokes her clit. "Say please," Jordan reminds her.

You keep fucking her. The buzzing of the phallus against your clit is driving you crazy, too. You can barely keep it together to keep thrusting into Emily. Your eyelids are fluttering, your legs shaking. But you're determined to do this properly.

"Please fuck me," Emily mutters. "Please slap my ass. Please, please." Her voice breaks, and she can't speak anymore. Her mouth continues to move in moans and in fruitless efforts to keep asking you to fuck her.

You oblige her, driving the vibrator deep inside her over and over again. You leave bright red marks on both of her cheeks, welts that smart when your grope her ass roughly.