I'm looking for a yaoi, possibly a one shot or side story, where the uke is a power bottom who calls himself the "butterfly of the night". The seme is homophobic but somehow ends up in the gay sector of downtown. I think the uke was his coworker, so he was surprised to see that his coworker was at a gay bar.

I think the uke convinces the seme to have sex with him by offering to "protect" the seme from a guy who supposedly likes rough sex and toys, but in reality that guy was a soft cuddly gentle bear and the uke was just lying to convince the seme. I'm not sure about this last part though. I might be mixing it up with another manga.

This sounds like Kiken na Otonari-san by Nanami.

Not sure about the second paragraph, but I've encountered a similar subplot in Miwaku Shikake Amai Wana.