A soda siphon or whipped cream charger used to inhale nitrous oxide. A small metal canister (the bulb) is screwed into a chamber on the side of the bulberator in which it is cracked, filling the canister with N2O. This is then inhaled to produce short lasting dissasociative / hallucinogenic effects.
"Time to crack out the nitrous . . . Where's my bulberator?"