I am 53. Have had 5 c-sections. This pain started just a few years ogo. It does go away shortly after the orgasm subsides. It's not debilitating but uncomfortable to b sure. I am wondering if it might b bcuz of anal sex in past.
It may not be that she is having anal sex, don't forget, everything is very close together especially in that area od our body.
I get a terrible spasm pain after an orgasm in my lower left side of my stomach, it takes a few minutes of a lot of pain to go away(longer than the orgasm haha). The gyno. says it is an intestinal spasm and the g.i. says he does not see anything after testing.
I suggest you make an appt with your Gyno, but it could be an internal hemorrhoid (I had the problem when I had a hemorrhoid) or constipation.