Someone jacking off using large portions of caked mud.
Did you see that hill billy in the woods yesterday? He was mud jacking like a mad man!
by Smoots July 02, 2011
1 more definition
Uh...using poop as a masturbatory lubricant.
Steve walked in on his roommate and caught him mudjacking.
by IWhoAmNotHe October 07, 2009