Season 1: Episode 13: The One With The Boobies
Chandler accidentally sees Rachel's "boobies," so she decides that she needs to see his "thing" in order to even the score. Meanwhile, Joey finds out his dad has been having an affair with Ronni-the-Pet-Mortician since 1989. Feeling bad for his mom, Joey gets his dad to confess, which really screws things up, since his mom already knew and was happier with the way things were. And Phoebe dates a shrink who drives everyone nuts with his analysis of their personalities and problems.