A makeshift cannon for shooting potatoes, usually made from PVC pipe. The two major varieties are pneumatic guns, which rely on compressed air, and combustion guns, in which a flammable chemical such as hair spray is ignited.
Guy at the hardware store: "I love shooting spudguns, just be careful not to blow a hole through your liver".
(verb) To spray (ejaculate) a large amount of semen on a woman's body (usually on her breasts, rump, stomach, hair, face or chin, and usually after a vigorous round of super-hard pornstar-style sex.)