I take a long hot shower after a particularly stressful day at work. Afterwards I wrap a towel around my waist and sneak across the hall to my bedroom.
I thought I got across without being seen, but I was wrong. My little sister invited you over for the evening to study, or gossip, or whatever it is you girls do. You both went to bed, but you just happen to be heading to the bathroom when you catch a glimpse of my dash across the hall.
As you return down the hall after using the bathroom you stop in front of my door. You silently open it a crack, and peek inside.
You see me laying nude on my back in the center of the bed. My head is laid back and my eyes are closed. One hand is slowly stroking my cock, while I am gently massaging my thighs and stomach with the other.
Not wanting to get caught peeking by my sister, you push open the door just enough to sneak into my room, and close it behind you. You reach a hand down between your legs and start to rub your awakening pussy over your clothes.
I run my second hand up my shaft below the first, then slowly twist my hands up and down my hard cock. A bead of precum sits at the tip of my dick. I rub my hand over the head of my cock and let out a small moan as I continue to pleasure myself.
You push your hand down and into the waistband of your panties. As your fingers come into contact with your moistening pussy you let out a small moan by accident. You cover your mouth quickly with your other hand, but it is too late.
The sound startles me from my almost meditative state and my eyes pierce you on the spot. I jump up and stand by the bed with my hands placed firmly on hips. My hard cock throbs as it stands up in front of me on full display, I make no move to hide it.
"Get over here now!" I point at the floor directly in front of me, and you walk over with your head down in shame. You give me a soft "I'm sorry" as you approach.