What is Yk?
1.
To commit an unusually large, noxious, and possibly toilet-breaking bowel movement, usually in a public restroom or someone else's home.
Source: Internet fora.
"Man, don't go in there ... somone laid a YK!"
"Dude, I was on a date and I totally YK'd the chick's house."
See
2.
Used in the Bust Cap linguistic system, to fuck
"Bust this shit"
"Bustin"
"YK thrice, DT all day long"
"Chinnie!"
See