A gasp from the door

You hear a gasp from the direction of the door. You look over and see Brittney with her hand over her mouth.

"You were going to wait for me, Lisa! We were going to seduce Dan together!" Brittney says, a little whine in her voice. She is smiling, though, so she can't be too mad.

The thought of a threesome with Lisa and Brittney sends blood straight to your cock, beginning to inflate it while it's still embedded in Lisa's hot pussy.

Lisa rolls off you and props herself up on her elbows. "Oh, Brittney, you took too long in the shower, and I needed some relief! Besides, he's 19 and already starting to get hard again just thinking about the two of us kissing." Lisa looks down at your cock for emphasis, because it's at half-mast and growing.

Brittney beams at you and says, "Well, maybe if we actually kiss, he'll get the rest of the way hard." She moves into the room and climbs on the bed in front of Lisa. Her tits sway as she crawls up Lisa's body. She dips her head down to briefly lap at Lisa's pussy, and then moves up to her breasts, sucking each nipple just enough to make Lisa moan. As Brittney shifts up to kiss Lisa on her full lips, Lisa gropes her breasts firmly and pinches her nipples. It's now Brittney's turn to groan out in pleasure. You see their tongues flicking back and forth between their mouths.

Your stepsister was right, as your cock now points straight up, rigid as a flagpole. Brittney grinds her knee into Lisa's groin, setting her best friend into a constant state of moaning.