Rub faster against it...

You begin to let your body fully have control, your eyes start to close and your grip on the curtains tightens as you begin to quicken your pace. The slickness of the water paired with your own lustful wetness making your movements near frictionless and fluid. You hear him become more comfortable with his moans, the ingenuity of your jerk-off session seems to be just what your roommate ordered. You feel him slowly begin to thrust as well, little leans back and forth but you know he'll be be syncing up with your movements in no time.

"...uhn...uhn...Uhhn...!" you comfortably start letting yourself be vocal without shame, your own pleasure building up with haste. The act, the person involved, the fact you're not supposed to be a woman...all these factors adding up to perhaps the most lustful state you've ever felt. Your pace quickens again as you feel yourself reaching a climax, you open your eyes to watch yourself sliding back and forth along his cock, the sight almost appearing as if he's fucking you, such a thought driving your lust further cause you to speak. "Oh yes...oh yes...come on..." followed by more moans and noises from you.

You hear him say in response, "Oh yeah...just like that....keep at it...almost there..." as he now matches your speed with thrusts, he grabs the rail for the curtains for leverage as he continues to lose himself in pleasure. You feel him tremble here and there, twitch a little and you know you're achieving what you wanted. You know he's on the brink as he begins to draw out his deep moans.