look up any word, like cunt:
It's a broader term than couch potato. It's not really being lazy but just relaxing, chilling. Doing stuff but not doing anything specific just going with the flow chillen.
Watchin tv waiting for someone to text you? You're buttchillen.

WuBrah: Yo sup let's play Dota, you busy?

Mikey: Nah man just buttchillen, let's play.
by Shuroku June 22, 2012