The act of jamming both your thumbs up a someones anus and proceeding to twiddle them around like you are using a game controller.
Person 1: Hey man are you still with your girl?
Person 2: Nah man she broke up with me after I gave her the ole Muddy Thumpkin
Placing the right thumb in the vagina, and the left thumb in the butthole.
My wife moaned and groaned as I gave her a no-lube double thumpkin.
Close relative to the Blumpkin; The act of masturbating while taking a poop. Ass must remain unwiped.
After taking a Bludumdump, I figured I'd give myself a Thumpkin. Two for one wipe special
The act of receiving a blowjob during a fist fight.
I would have won the fight if I wasn’t distracted by getting a thumpkin.
When one has an erection (he) tucks his hard manship between his legs not allowing her or him to see his erection. Upon checking for head erection he opens his legs allowing his hard erection to hit her square in the face. Thus you have the thumkin pumpkin
Yo bro gave my lady a thumpkin pumpkin last night and today she has a black eye!