What Malfoy shouts at the good guys at the end of "adult" version of Harry Potter and the Deathly Hallows.
Draco caught sight of Harry, Ron, Hermione and Ginny staring at him, nodded curtly and shouted "what yo' mudblood asses doin' starin' at me mugglefuckers!"
A term originated in the furry fandom. It means someone with a short penis. The word came from the thought that anthro creatures, such as wolves, have a long muzzle. If you can get past the muzzle with a blowjob, you are okay. If you can't make it (past the muzzle), you are a muzzle fucker.
"Did you hear what <asshole person> did to my carwindow? That Muzzle Fucker threw a rock through it!"
A person of less expertise, experience, knowledge, and understanding that causes great frustration to someone with greater knowledge, experience and expertise.
Brian is such a mugglefucker! He totally just screwed me over...I feel so mugglefucked by him!
Sticking your hand up a girl's anus, as in fisting, and you grab onto her intestines and pull them out. People who do this are called Dutch Munklefuckers.
"Dude I stuck my hand in my girlfriend's ass and pulled her innards out! It was hot!"
"DUDE! You're such a Dutch Munklefucker!"