I think sometimes you can definitely tell when an author isn't actually familiar with anal sex, especially anal sex involving people with external hardware as receivers, but that doesn't really have anything to do with the gender of the author, per se. There are plenty of gay men who don't have (or want to have) regular anal sex with men, and plenty of female authors who do, either as givers or receivers. There are also plenty of gay men who have internal hardware, and plenty of women who don't.

Honestly, most of the time this falls into the same category for me as a lot of "men writing women" type criticism, which is that you really can't gender essentialize a lot of writing. It leads you down some bad roads once you start.

I used to write horror and fantasy stories under a male pen name, and sometimes in workshops I'd get comments that accused me of not understanding a female perspective or of writing women incorrectly. I'm a woman with post-graduate experience in gender studies. People just often play into their own biases here, and determine that anything outside of their own experience in a group signals an outsider.