Quote from Phoebe in The One That Could Have Been (Part 1)
Phoebe: Maybe you need to spice things up a little. Ross: What do you mean? Phoebe: I don't know. You could tie her up. She could tie you up. You could eat stuff off each other. You know, dirty talk, Ménage à trois, toys, role-playing. You could be the warden, she could be the prisoner. You could be the pirate, she could be the wench. Ross: Okay, I think I got it. Phoebe: Or you could be two stockbrokers, and you're rolling around naked on the trading floor and everybody's watching. It never happened.