There's a thread I posted here about how to find those - as well as how to find the only gay sauna in Hatyai. I can't recall it but I did post the same information at my blog. Here's the link -
The Rowdy Reprobate: In Hatyai - how to find the gay sauna and bars
I'll be going to Hatyai again soon so if there's any outdated information, I'll be updating it after that.