This is one of those "more about sex as it relates to poly" topics, so if that doesn't interest you, please click past this post. :)
One of the things that S and I have noticed in relationships with other women, was that it's kind of easy to get a bit mixed up in bed. Out in the mono world, one of the most heinous crimes that we are warned against is the use of the wrong person's name in physically intimate situations. Poly can take that up to a whole new level! This one was kind of more of an applied practical knowledge thing. What happens when you mix up the preferred sexual styles of your lovers, either when you're having couple time with one, or actually in bed with both?
Let's say Lover A enjoys a slow sensual touch, while Lover B is more a fan of firm and rapid, or that A goes ga-ga over light flicks of the tongue, while B is bored by that experience. Here you are, trying to be the best lover you possibly can to all your partners, but you get mixed up. It happened commonly enough that I started using a reminder phrase to help shift gears: "Wrong Woman!"
I fully think I got off easy on this one, as there are just some absolute differences between male and female bodies that make it a bit more contrasting to transition between lovers of different genders. I'm less likely to forget and play with nipples the same way in the absence of breasts. Unlikely to give cunnilingus instead of fellatio when there's a cock in my mouth. Alas, poor S wasn't quite as fortunate! Yeah, he was feeling the pain...
So, here we are in intimate space, either just the two of us, or with another lover, and suddenly, it becomes obvious that the way I am being touched isn't the way that S knows is most effective. In fact, he's doing something the way that flat does it for his other lover, but doesn't do much for me! Is this the time to have a conniption about my lover getting me mixed up with someone else? No way. This is the time for a gentle reminder that, while the effort is appreciated, this isn't the body you're looking for.
Most of us have experienced the phenomena of needing to do a bit of retraining when a new lover enters our lives. Learning new ways of touching, ones that specifically work for the person you are with, rather than what you imprinted on in the last relationship. When having more than one relationship/partner simultaneously, it gains a bit more gravitas.
This can get a bit more touchy (ha ha!) in group situations where you are literally pleasuring more than one person simultaneously. Sexual ambidexterity is something that takes a bit of practice, and some of us are not going to be as skilled as we'd like, so help from the partners in question can be really valuable when getting off (course).
Of course, this all goes back to basic communication, but it seems that many perfectly good communicators go all pre-verbal in bed. If needed, cut conversation down to simple words. Slower, faster, harder, deeper, stop! Do not, I repeat, do NOT just allow the opportunity to improve the situation pass you by out of reluctance to bruise someone's feelings. Any lover worth their salt would want to know that they've slid into a pattern that isn't working for you, because at that point, it isn't working for them either.
Be bold! Embrace the stern challenge before you of being an amazing, varied lover to all your partners, in the special ways that they enjoy as individuals. Not one of us is the same, and in the arms of our partners, we are loved uniquely.