look up any word, like spook:
 
1.
An expulsion of gas from the anus whilst moving or walking which makes a noise reminiscent of laughter.
"Larry let loose a mighty bumchuckle, much to the chagrin of the woman walking up the stairs behind him."
by Grm September 29, 2007
 
2.
When, during anal sex, the giver (or receiver) laughs, giving a surprise sensation to the non giggler.
man: "have you ever had a bumchuckle?
woman: "no? what is that?"
man: "here, i'll show you, HAHAHAHA"
woman: *screams*
by Naurog February 17, 2009
 
3.
a bubbly sounding farty.
gross! did you hear him just bumchuckle in public!
by SpindleShanks May 29, 2006