To achieve ejaculation within the anus of another.
See "donkey punch"
by Harry Merkin August 06, 2002
A condition where fecal matter gets on your nutsack after taking a nice healthy shit and then wiping your ass from back to front.
That shit on your underwear doesnt look like skid marks, i bet its from mudnuts!!!
by IBStudent April 02, 2006
doin a girl in the butt then pullin out and shootin it in her mouth.
my hizo wouldnt stop bithcen so i muddnutted her.
by the gavo69 February 12, 2003