Aliasing arse → butt
Link to alias

Reason:

I don't think there's really much point, but as you've suggested it there's no harm in accepting IMO.

Yeah why not. There's so much slang for body parts that it's hard to tell what people are going to use and we might as well have a fallback for the more obvious ones (as opposed to the less obvious ones like "bearded clam").

Approved.