A fork of Rural Dictionary
Smack On means to propose a fight with someone. Generally in a joking manner but can definitely can be used very effectively in a real situation. Smack On is closely associated with the term "punch on".
Joking: Luke: "You suck apples" Brad: "Smack on cunt" Serious: Josh: "I fucked your ex on a trampoline!" Ryan: "Smack on cunt!"