A defining moment when you know someone has gone off the deep end. Inspired by Tom Cruise's recent behavior on Oprah. Also see jump the shark

Other examples of celebrities jumping the couch besides Cruise:
Angelina Jolie making out with her brother at the Academy Awards.
Michael Jackson dangling his son from a balcony.
Farah Fawcett drunk and incoherent on the Late Show with David Letterman.
Mariah Carey half naked, reading a love letter to Carson Daily on TRL.
Whitney Houston's "crack is whack" speech on Dateline NBC.

Based on Tom Cruise's display of affection for Katie Holmes on Oprah. To jump the couch is to say a person has lost the ability to deal with emotions in a reasonable way. Communicating some form of insanity to those around.

to exhibit strange or frenetic behaviour

To jump the couch is to go crazy for someone on national T.V. by ''jumping on thier couch'' Can be used on people you know personally too. Also see jump the shark Tom Cruise

refering to Tom Cruise's display of affection for Katie holmes. Meaning, did something stupid or idiotic

It's also a phrase used in the fraternity world when an active member puts his own status on the line for a rushee. He tells the house that he is "jumping the couch" for a rushee, and that the next vote to allow the rushee into the house is a simultaneous vote to keep the active in the house. Direct opposite of blackball.