A commonly used term to describe severity or intensity of of 'chilling out' or relaxing.
Relaxing to the 10th degree.
Chilling out like no other.
"Nothing dude just chin-chillen."
"Hey brotang what are you up to tonight?"
"Probably not much, just chin-chillen right now."
"Man I really need to relax, big time"
"Come over here man were all just chin-chillen"