I was invited to watch another couple once, I was just a spectator, but was permitted to jerk off while they performed. That was one afternoon I won't soon forget. Damn that was hot. I think they enjoyed watching me as well.
Another time getting a sensual massage, I asked her if she would masturbate for me. She positioned herself beside so I had a great view of her pussy. She came twice while I was stroking myself, but I held off so she could finish me later. I will be repeating with this person, but I don't think she wants reviews here, so please don't ask her name.
So, would I participate if there were other guys and female(s) just pleasuring each other, very likely I would give this a try.
Just 2 guys watching porn and jerking, hmmm. Would have to give that some thought but probably would no be opposed to trying.