doesn't exist, if you mean "shit stain" or "turd/poop stain" it makes sense but your ass physically does not stain, if you use this word you're a moron.
"Damn I got an ass stain dude"
"You mean shit stain you idiot"
A small piece of information. Derived from the word ken, used often in the scottish language and is synonymous with knowledge.
Person 1: "Hey I don't get this shit. How do you solve this problem?"
Person 2: "I got that one. Give me some kenlets on this assignment and I'll help you w/ that one."