A gay sex act performed in a public restroom lacking partitions between stalls, in which two seated participants take turns bending over sideways to perform fellatio on one another whilst simultaneously defecating in their respective receptacles. Generally not performed sequentially ("I'll do you until you blow out both your loads then you do me, ok?") but rather in rapid alternating bursts of a few seconds duration A-does-B then B-does-A. A professionally-executed blundonian blumpkin maneuver results in a virtually seamless and volcanic four-way explosion and is a true wonder to behold.
Conversation in public restroom:
Gay Guy #1: Are you thinking what I'm thinking?
Gay Guy #2: Blundonian blumpkin?
Gay Guy #1: Ha!
Gay Guy #1: Are you thinking what I'm thinking?
Gay Guy #2: Blundonian blumpkin?
Gay Guy #1: Ha!
by Chad Wooley February 23, 2006
While orally pleasuring a women from behind, you proceed to mudder boat her while she shits all over your face
by Flumpkin Bucker October 23, 2009
A rumble blumpkin is the same as a blumpkin (getting a blowjob while taking a shit) except the recipient has explosive diarrhea.
I wanted to get a blumpkin from your sister after dinner, but we ate Taco Bell and it turned into rumble blumpkin instead.
by chuck-fucking-norris December 14, 2011
by Caexar January 07, 2007
The act of receiving oral while taking a dump, while also giving oral to somebody else who is defecating.
by sartori April 02, 2004
After receiving a Blumpkin (fellatio while defecating on the toilet), proceeding to place the lucky lady's head on the seat and smashing the lid on her.
I had the worst blumpkin ever. She didn't even swallow the goop. I had to make it a smashing blumpkin to remind her to take her protein next time.
by Tim Branberries February 01, 2008
by Swat23 January 03, 2006