Sin biscuits are when a cat makes biscuits (kneads) in an attempt to reproduce or rub one out. This is done with either another animal or an inanimate object like a stuffed toy.
Susan: Look how cute my cat is! He's kneading that toy so intensely!
Mark: Hate to break it to you, Susan, but them's sin biscuits.
Mark: Hate to break it to you, Susan, but them's sin biscuits.
by Porthole in the Dark July 4, 2020
Noun, a little hunk of something delicious and sinful; a guilty pleasure; something fattening and shameful to eat. Can also be used to describe a person who is naughty or too good looking or too over-the-top. Delicious, obscene.
What is that chocolate mess you are eating? -Oh, just a little sin biscuit I whipped up.
or
Did you see that hoochie outfit she's wearing? -That girl is a sin biscuit!
or
Did you see that hoochie outfit she's wearing? -That girl is a sin biscuit!
by anthnerd November 13, 2009