What are some fun things to try in a FFM threesome?

Sitting in a corner, crying because you just prematurely ejaculated and now they’re having more fun without you.

Source: my ex-wife and her new lady partner.

Do's:

Be respectful. Concentrate on the ladies. Make sure to bring your A game in regards to oral and finger play. Always be touching or tasting, even if it's just a light caress while they're concentrating on each other. Pay attention to their responses. Go with their flow. Make eye contact. Respect any boundaries, whether established on the fly or beforehand. The latter is especially important if there's already established relationship(s) in the group.

Don'ts:

Don't be selfish. Your dick is not a gift. Unless something goes horribly wrong, it's gonna get action. Be patient. They will let you know in no uncertain terms when they want it. Don't favor one over the other (especially if one is the "new girl"). Don't be intimidated if they want to bring toys into the mix. Toys can do things you can't, and vice versa. Don't let pride get in the way of their pleasure.

tl;dr If you make it about them and not about you, the odds of getting an encore go way up.

Best of luck, and enjoy.

It really depends with how bisexual the girls are.

If they aren't at all then it's gonna be you servicing two women. Be hydrated lol.

If they are bi then the pressure is off for you to have a boner all the time.

Fun suggestions if the girls are bi:
Double blowjob, fuck the space between their lips.
Have them 69 and switch between mouth and pussy on both sides.
Trade who's in the center. First you laying down with them on top. Then either girl laying down. Then either girl in doggy eating out the other girl.

The possibilities are many. Just remember the worst position for a particular person is where they are doing all the work, so try to avoid those positions if possible (e.g. you banging one girl and fingering another at the same time, or one girl blowing you and fingering the other).

It’s exhausting.

No matter what you do, after you bust a nut, they just keep going.

You think to yourself “man, I gotta get back in there!” But they don’t really want you back.

Keep the focus on them. You'll get yours, but make sure they get theirs. If you're not above some chemical assistance and can get your hands on a "little blue pill" then you don't have to worry about popping off too soon. Remember, have fun!

Don't plan too much because they are really the ones running the show. Just follow their lead.

Find more men? Honestly, if its FFM, it's about the women, and the male is their toy. Assuming your the male, do as your asked. They can go for hours, you can't.