The act of receiving oral-sex while having explosive diarrhea.
Guy: Dude, your sister got drunk and gave me an Ultra Blumpkin last night.
by Gettin' A. Beejay March 21, 2010
When one person receives oral sex from two or more people while dropping a deuce. Supposedly pleasurable, however it is extremely difficult to achieve release from both ends at the same time.
Lucy and Ethel gave Fred an ultrablumpkin for his birthday, while listening to the radio.
by TheMishkin June 02, 2006