A person who is exceptionally skilled at cashing a bowl of marijuana.
Stoner 1: I think this bowl is cashed
Stoner 2: Yeah it definitely is. You should ash
Stoner 3: Naw man, lemme try.
Stoner 1 passes the piece
Stoner 3: Take notes. This is how it's done.
Stoner 3 successfully takes a hit and gives it back to stoner
Stoner 1: Oh shit, I didn't know you were a cashmaster!