I was contemplating informing Johnny Mac that the term was "bung-holes" but then I reconsidered in view of the cross-Atlantic cross-talk and, well, yes, "bum-hole" fits perfectly (wry grin spreading) oops, there I go again (no matter what I say now I'll just get in deeper and deeper). In the American mid-west "arse" was a semi-decent way to say "ass" and not draw too much heat. It was like announcing "I don't REALLY talk this way but I must in this case..."

I don't know at what point in history the lowly beast-of-burden's name got confused (or maybe just "fused") with the that which sat upon it, but it did. Eventually along came the "horse's ass )or arse if you prefer) and there was NO confusion here. The term was plainly understood.

If a horse mounts an ass its offspring is not a horse's ass but mule (sterile male). If I remember right if an ass mounts a horse then the offspring is a sterile female called a "jenny". I've never heard anyone proclaim "Well I'll be a horse's jenny!" but I have heard the term "mule" to describe various sorts of behavior and attitude. It runs from stubborness to smuggling illegal drugs, from strength to stupidity and so on. Oh! I seem to recall that it also describes or symbolizes an American political party. I don't know if that is because of the loud, obnoxious braying, the stubborness or perhaps all of the above.

Now before you get all partisan on me I also seem to recall a video of an elephant with its trunk up another elephant's "arse" for an unholy amount of time. When it finally pulled it out it immediately stuck whatever treasure it found there, in its own mouth and finished the job of digestion (or recycling).