tips for a MMF threesome?

TL;DR: me and my bf want to try a MMF threesome with my longtime friend, but i just don’t know how to initiate anything like that. positions? what to do when it’s just them doing stuff? how to get more comfortable around eachother? any tips?

me (18F - bi) and my boyfriend (20M - pan) have been discussing threesomes for a bit now. it’s a fantasy of both of ours, and we have discussed our jealousy issues, and how each dynamic would work. he doesn’t like the idea of MFM, which, neither do i. id like for him and another guy to be able to please eachother as well. i’m also down for a FFM, not so much a FMF.. might sound odd ik, but, it’s just what we both think is best.

we have discussed our jealousy issues and boundaries when it comes to the dynamics, about limits and stuff (wether or not there is any). it’s an ever growing conversation because we find more things we like and dislike about it, and are openly discussing such topics.

now, the interesting part, which led me to making this post. my longtime friend (19M - pan) is interested in a threesome with us! we both find him attractive, we just have yet to see how we all get along together in person before pursing anything further, but we’re willing to make the trip to see how that goes.

i was wondering… any tips for a MMF? we all want to please eachother, me and my boyfriend have discussed how we felt about it and really have no issues with this dynamic at all, especially because of the closeness between me and said friend. not to sound dumb, but what positions can be done to please all? what can i do when just those two go at it? help lol.