NO!
It’s called PLEASURE. Jeez! Men and women have different erotic hot spots. The prostate is a major hot spot for men, there’s a concentration of nerve endings there. Too many men are insecure about their sexuality which leads to questions like yours: is it a “gay thing” to massage my prostate?

Stimulating the prostate actually intensifies a man’s orgasm and can delay ejaculation which makes it a good thing for BOTH parties involved! Men have their “g-spot” there, just as women have their own “g-spot”. It’s absurd to deny yourself pleasure just because you think it’s this weird, stigma thing that will turn you gay if you try it.
No! You have an erotic hot spot, use it! More women would absolutely utilize it during sex if guys weren’t so uptight about it. They really would not have a problem with slipping a finger up there while giving you a BJ. It’s the “taboo” weirdness that straight guys place on it that ends up making you ignore a really fantastic source of pleasure. This is not about your sexuality! It’s about orgasms and making them better! It’s WHO you want to fuck, not HOW you fuck.
Anal play does not make you gay. Having sex with men makes you gay.
It’s really that simple.