Irish for ejaculating your "load", which contains semen and sperm, all over a sluts face, and hopefully she will have the common decency to fuck off afterwards.
A common practice in Ireland usually without the slut fucking off as they want more muck.
" jasus would ya look at that whooer!" said a Fat ugly Irish man
" She deserves the muck" said his even fatter girlfriend
"BLow the Muck on her face" said the fat ugly Irish man with a grin on his face
" No thats my dinner" said the irish model (Fat woman)
When finished busting a load on someone, one proceeds to take two pieces and bread in which they scrap the remains onto the bread and feed it to the recipient.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi