look up any word, like ratchet:
 
1.
After a good doggie style romp, the jizz left on the tip of your cock gets rubbed into the chicks bunghole. A little poop gets mixed in during the rubbing and you muck it up.
After banging the bitch doggie style, I blew on her back. Then I mucked it up for a bit, before banging her sister.
by Dr. Davidoff Vilson March 28, 2005
 
2.
Muckit is when you take your cock and push it around in your bitches asshole...you smoosh around her shit and your gizz.
After I was done banging my bitch, I mucked it up.
by Dr. Davidoff Vilson March 21, 2005