This is coloquial, but if I'm high to the point where it's somebody else's right to know I mutter "I'm cashed" before I wander off/pass out/beat off in the courtyard/die/cagebrawl with Jesus/paint my penis red and make imprints on all the doors in my hall except mine {usually around four a.m., if you live here }/punch nuns/make a snowman/cannibalize a crippled monk.

It originated as that all the smoke had been conductively converted to ash, which evolved to a term for red eyes (mostly in the surrounding rural area), at which point started hearing it for this when I joined the friendly not-quite-neighborhood general crime syndicate in an outlying farming community. Over time, I developed this into my own lexicon as a reference to when I was so stoned I couldn't see straight (hence the evolution from the redeye phenomenon). In addition, I have become to see this term as a reference to being greatly rewarded, such as in the case of cashing a check or cashing out of any system of retaining money for gradual cumulation.