ass apron 

A piece of clothing that wraps around the waist hiding the ass most popular forms of Ass Aprons are sweaters or long sleeve shirts

I was walking in the mall and this gorgeous girl was coming my way, when she walked by me I looked back to get a look at her ass but she had it covered with her ass apron

ass apron by NickyLags July 30, 2010

Ass Apron 

A term that a baseball umpire uses when a ball player argues the call with them in a very ignorant manner.

Player - "That was a shit call!"
Umpire- "Youre an ass apron!"

Ass Apron by AA-ron Wood April 24, 2013