overdose; generally fatal, in so much as that one's system cannot handle the quantity of drug being pumped into it; hence death; generally a body-wide systems failure.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.