I rarely have a 3 some with a couple. They often get uncomfortable after the fact unless you totally don't know them. I prefer to have them with 3 single people and it's no strings attached.
I don't have a preference for what I want my partner to wear. It really doesn't matter to me as long as they're comfortable, but I feel sexiest in a sundress or little tank top and skirt with nothing underneath.
I've had every combination before and they're all unique and amazing in their own right, but if I had to choose just one, I would take 2 guys and myself. I'm a greedy cum slut and love multiple dicks in me.
In high school I was on a traveling volleyball team and I regularly had sex with my coach and the assistant coach who were both married. I also had sex with my boss when I was a waitress.
If it's someone I'm attracted to, I'd probably go over and ask if they wanted help. I'm sure my mouth, pussy or asshole would do a better job for them.