a code word used to cover the fact that you are in fact about to partake in a "mash-up". the logic behind this word is simple: spud comes from potato or "mash" and "don" is an easier way to say down which is opposite to "up".
pete: hey dave, you going for a spuddon later
dave: you bet my sweet ass i am
one who has alarmingly dark penal discharge. Black cum. This term serves well as an insult for those writing a list of rude name-calls for each letter of the alphabet (see 'chudge') and can't think of anything beginning with i.