[NSFW] How do you relieve cramps "back there"? (See de-tails).

This is a bit embarrassing. Every now and again, with no apparent triggering mechanism, I get a sudden and very painful cramp in my anal sphincter muscle. It aches enough to make life miserable and takes an hour or two to finally go away. It’s not like a cramp in a calf muscle, where you can flex your muscles to work out the cramp.

Is there some kind of muscle relaxant or pain filler you can squirt up there to ease the pain. At it’s worst, it is so distracting I can’t get much done aside from walking around groaning. The pain is enough that if I thought massage would work, I’d let some big Bubba put his cream in the chocolate vat just to get it to go away.

Anyone else have problems with this? If so, how do you make it go away? PS: I’ve had this off on on for 40 years, so it’s clearly not some sudden new disease needing an assadectomy.