A moan from her bedroom

The noise sounded an awful lot like a moan, coming from Rachel's room. Thinking it as Rachel still struggling with her hangover you ignore it. Seconds later another muffled moan is heard by you. It sounded like a moan of pleasure.

"Surely not!" You whisper to yourself.

Another moan, this time louder echoed throughout the house. With a grin you leave the kitchen and quietly go up the stairs. Another moan reverberates through the house.

Walking on tip toes you eventually make it across the hall to just outside Rachel's room. Another moan comes from inside the room. You reach for the door, but hesitate. The risk of being caught is high, and your friendship with Rachel will almost certainly be destroyed, but the thought of seeing Rachel in her full glory, pleasuring herself is an enticing one.