this is a slang word used by hoodlums/gang/wannabes type shit, its another way of saying like a knife or a gun/ some kind of weapon that will fuck you up
person 1 : bro why is he walking to us??
person 2 : RUN NIGGA HES CLUTCHING HIS TOOL
Tool" is just a slang term for penis. It also has other meanings like Calling someone a "tool" is a less profane way of calling them a "dick" or "cock" or "prick". Or a asshole
1: yo bro stop being a damn tool and throw away your fucking trash man.
2: Me and And Ashley had sex last night I put my Tool in her :)