a term used to insult a friend when they are behaving in a disgusting manner, possibly ladish or yobbish. However it's used in a humorous way and only applied to friends.
1. Oi stop ketching about.
2. why you acting like such a ketche?
3. you dirty little ketche!!
When you shart, and and the blood from your cancer and/or rectal infection turns the poopy soup into a tomato flavored red paste, like ketchup.
Origin: While playing I was playing Pokemon (cause I'm a beast), my brother tried to say "Ash Ketcham," but failed like a woman. Naturally we made it into a word.
Chaz- *farts nastily with much gusto* "Aww man, I think I just made ass ketchup... Darn cancer/taco bell."
Bob- "Ever since Todd developed that digestive disorder, the only thing he has had on his burgers is ass ketchup."
Sort of like, "fuck", or "damn", but you can say it in front of children, and on NBC in the 1960's. And, yes, this is from the Monkees. However, this is not how they used it. I would just like to see it get used as a swear word.
Michael: "Oh, Micky, your tireblew", Micky: "Kretch!"