While you are giddily playing with your new flesh, experimentally sticking a finger in and almost laughing at the tingling, you don't notice someone is opening the door. "Hey, are you in here? I--" she starts as she walks in, bringing you back to reality and quickly moving your hand elsewhere. She asks somewhat confused:"Um, why are you moving your hand around in your pants?" You feel yourself blush and answer almost automatically "oh nothing, just adjusting my underwear...it felt kinda uncomfortable." You move your hands out of your pants completely and hastily make your way to the door, still blushing a bit at the prospect of being caught in the act by this person.
As you walk out of the door, she says "You haven't forgotten about tonight, have you?" Oblivious as to what she's talking about you reply:"Oh but of course not...how could I." She gives a slight chuckle:"Heh, dunno...just that you're usually the kind of person to forget things."
You close the bathroom door behind you and must admit to yourself that you indeed have no idea what's supposed to happen tonight, but you are not going to admit defeat - and lack of memory. Oh well, you think to yourself, I'll just wait for tonight...