An idea invented by my friend and I on a drunken night out; piss-clips are large clips, similar to hair clips, which are used to hold up the rolls of fat on clinically obese people so that when they sit down to piss the excess fat doesn't sag into the toilet and get in the way. Can also be used as a term of abuse, for example:
"She's so fat she needs piss-clips!"
or, more simply:
"You stupid piss-clip!"