Quitters
Jeans or pants that fit tightly around the bum when you first put them on, but as the day goes on they get saggy and unflattering. Could also refer to socks that lose their elasticity during the day.
Example:
"Here it is 4PM and you can no longer see that I have a butt, these jeans suck, they are such quitters."
"Here it is 4PM and you can no longer see that I have a butt, these jeans suck, they are such quitters."