A term used to show off when you have the nuts in a poker game. After going all in and everyone calling/folding, immediately flip your cards, yell out "muck yo shit," and start collecting the chips.
This term can also be used in everyday life. If ever you need a catchy phrase, it is fair game to say, "Ayo, muck yo shit reggins..."
"Nice full house John. Wow Satyam you have a full house too! No way Mikey Mike. You have four-of-a-kind. Thats too bad cause I got the straight flush. Sorry boys....MUCK YO SHIT!!!!"
"That bitz told me she liked me, but I was all like MUCK YO SHIT"