Don't ask for or expect more, treat this as a one time growing experience and be grateful for that.
Try to predefine boundaries so that you know what both partners are comfortable with, what they do and don't want from you , and what they do and don't want from each other.
Everyone has different kinks and levels of comfort being open honest and upfront about those helps make it a good experience for everyone.
Communication is key Make sure that everyone is comfortable asking for what they want and saying what they don't want at any point throughout the night.
Make sure that everyone is actually interested in it and not a "for you" kinda thing. Like make sure the females are as hot for each other as you are for them (or whatever the gender/person setup is).
Also, wait a week. Actually contemplate if this is purely for your satisfaction, or something everyone wants. If it's a "gotta happen right now", don't do it in a relationship. If it's a hook-up, use your own discretion as you probably already do with partners.
Not the OP but I don't think that's what they're trying to convey. Definitely make sure you're getting what you want out of the situation as well but also make sure everyone else involved actually wants to be there and is interested in everyone else. It's also possible that you can enjoy a three-way where two of the people are mainly just into the third person but everyone still should be comfortable and happy with what's going on.
I guess just make sure everyone knows they're free to speak up if something gets uncomfortable and make sure any boundaries are clearly established beforehand. And have fun! I highly recommend being the foundation of the Eiffel tower.
Sometimes, I have gay threesomes. It's obviously not the same, but what's not gender related and important to me is that nobody feels being put aside, and forced to just watch the two other ones having fun (unless it's a kink, of course)
I view most of the content in this group as fun porn. BUT if you want to deal in reality your comment is certainly correct. No one is going to enjoy a sexual experience if one of the participants is not comfortable with how it is proceeding. When in these situations I constantly ask "are you OK? If you are not enjoying that let's just stop."