BumCum is when you give your girl so laxatives and you wait til she gotta shit so you and 3 friends nut in her ass and then one of you get up close and let her shit it all out to make a stinky sticky liquid and you eat that shit up.
Stephanie visited me ome last night and filled me crapper with 11 softball sized bumdumplings....the lass may want to have er shat hole checked prior to reimbursing the town for the sewer damage