Have you ever wonder what Monica and chandler are taking about when phoebe find out about them. Is like in one shot they are having an interesting and intellectual conversation and the next shot they are desperately taking each other clothes off! It's so funny to imagine the actual serious conversation that leads them to have sex right there!

I’ve read that they have actually released the dialogue from that scene! The actual lines are:

Chandler: Look, we have to talk. Your shirt is really bugging me.
Monica: Wow, that’s so weird, ‘cause your pants are really bugging me.
Chandler: Well, let’s make each other happy and get rid of them.

:D