1 definition by Vitus17

A term regarding the sex of people who are 'just friends' at a slumber party or sleepover party.

The term originally described the mattress these people would sleep on, but now more generally describes the practice of two friends having sex while retaining the image of being just friends.

The term was originally coined by Conor Oberst and the Mystic Valley Band in their song Air Mattress.
Jenny and Craig slept on the air mattress last night.

Dave: "Craig man, you and Jenny are sleeping on an air mattress? NICCEE"
by Vitus17 October 13, 2009