German Knuckle Cake (noun) A slang term for fisting someone is the ass.
Her asshole was so big I could have fit a German knuckle cake in there.
by Pox March 08, 2006
Fisting with a vengance. Giving the anal blitzkrieg.
Chris loves to get a German Knuckle Cake for his birthday!
by Big_Daddy_Shame_Train March 24, 2006