What's the meaning of "tibbies" in this context. The quote is from one of Richard Laymon's books:
"You killed her, so you get first tibbies. So take the head. Everybody does. 'cause the brain's the best part. So you take first tibbies on the head, and give it to me."
I googled it and the results were mainly a dog breed which is not obviously how it is used in this book. I even checked Urban Dictionary but couldn't find an appropriate definition that would fit in this context.