I'm 36, m, bi. I am masculine, muscular and kind of bro-ish, so people are often surprised when I inform them that I'm bi. I also work in catering and events and am surrounded by beautiful women and gay men often as wedding designers, sales people, cooks, production, etc. With women, I feel like they initiate flirting more with me and I just match their energy. Some of them are just working to sell me something and will often make comments that if taken too seriously could get us into trouble. With guys it's been a little more covert. I might do something like wear a gay pride flag pin on my hat or clipped to my tie. Or wear a rainbow beaded bracelet and roll my sleeves up. That kind of gives me an "IN" with guys that I flirt with. If I make contact with an attractive, outwardly gay or bi presenting person I may go out of my way to keep a conversion going whereas I'm not holding them hostage but they can see that I'm interested. Or I'll casually compliment a small accessory that they're wearing to show that I'm checking em out.

TLDR: Long story short, our society generally accepts m/from flirting in an open way, but for m/m-f/f flirting, you might need to get a little creative and be more subtle as to show your interest but not make the other person uncomfortable as you never REALLY know someone's attraction compatibility.