I've never had any male masturbation buddies. Only few female friends were masturbation buddies. My first was when she and I were teens. Oddly enough we never had sex with each other until we were in our early 30's.
In my 20s I had a friend who slept over in my apartment. We watched each other masturbate for a few years. On a few occasions it went a bit further. He would rub my cock and I'd rub his. We had oral sex a few times and swallowed cum.
I didn't when I was young, but have had some in the last 10 years. I'm 61 now. Generally we start by watching porn, then lowering our pants and underwear. It's fun talking about the things we like about the women in the movie... her looks, body, etc. Sometimes we end up stroking each other.