look up any word, like plopping:
 
1.
Receiving Fellatio While Defecating Into a Cellar Sump Pump
Did you hear about Adams basement?
No, what about it?
That ugly bitch Rob brought to the party gave him a “Sumpkin” and it fucking reeks!
by Krzysiek6891 August 26, 2008
 
2.
while occasionally referring to a disturbing sexual act, can also be used to describe well-dressed, hilarious, drunken individuals in the southeastern United States; see: frat-star.
Man those fraternity guys sure are sumpkins.
by fratdaddyUT November 17, 2009