Quickly leave the room...

Realizing what I'm seeing, and that if Monica sees me that I'll be in for the shitstorm of the eon, I turn and leave the room, quietly returning the door to its original cracked-open state.

As I head back to the front door, it opens and Rachel walks in. "Hey, Ross!" she says, but I signal for her to be quiet. She immediately shuts up and walks over. "What's up?" she whispers.

"Monica's in there," I point over my shoulder to her bedroom, "and she's kind of..." I'm at a loss for words to describe that my sister is fucking herself silly, when suddenly a loud moan issues forth from Mon's room. Rachel's eyes go wide.

"Oh!" she says, catches herself and quiets down. "Oh!" she whispers. Another moan comes from Monica's room along with a: "Fuck yeah, Rach! Pound me with your strap-on!" Both Rachel and I do a double-take before tip-toeing back over to Monica's door.