29F - ass grabbing in gay bars

I’m a 29F, straight, but will go with my best friend to gay bars...but I can’t figure out why I get my ass grabbed more by gay men in gay bars/clubs or why they get excited when I’m at the strip club and thank my friend for bringing “a really pretty girl”? Any thoughts?...I don’t get bothered by it I’m just genuinely curious so I can understand how to perceive it...