When you are dabbed out, you are so high due to taking
dabs (
Butane Hash Oil) that you are in a state of (semi/un)consciousness.
It this level of high, the user is unable to take another dab, thus "dabbed out".
Tony: "Oh man it's so late but I haven't even caught
a buzz yet... Are you
tryin' to do another dab?"
Blake: *
zzz*
Tony: "BLAKE! Wake the hell up man..."
Blake: "Wha-... Oh shit. Sorry man I've been smoking all day, I'm dabbed out."