In reference to the movie Full Metal Jacket, Full Metal Tappin' involves an individual 'Taking a Blinker' off an empty cartridge or disposable, absolutely frying the user's esophagus and leaving a burnt charcoal taste stuck in their mouth.
Darius: yo whatchu got trav smokin on that shi smell like boof
Donte: Naw iss jus burnt as fuck he Full Metal Tappin' the jawn
Darius: Ah hell naw get this nigga a respirator XD