Crafts. You know, sewing, painting, working on things that often need more tools than you can carry at hand. I spend a lot of time fitting and repairing costumes while they are on the actor, so I frequently wear aprons. My purple pleather apron is falling apart, so I cut this one out.
Yeah, I can see how that might be confusion. It's not going to hang over my bum. I'll be wearing it like a normal apron, it just happens to be cut out from the back side of a pair of jeans. Hence Arse Apron.