A blowjob given while the recipient is on the toilet, taking a crap and eating Taco Bell all at once.
I let this guy talk me into giving him a Mexican Blumpkin but couldn't finish because it stank so friggin much. I vomited on him, giving him an Irish Blumpkin instead.
Takes two people, one takes a dump in the tank of a toilet while the other faces backward on the normal toilet seat dumping while giving the tank dumper head.
Yo, eff those tool bags, they wouldn't give us any beer so Crystal and I pulled a double decker blumpkin in their master bathroom and rolled out! Try flushin that bitches!