I recently got in a discussion with someone on the topic of "three-somes". This was brought up because my work has recently started carrying a larger variety of guides and manuals on the art of multiple sex partner interactions. The person I was speaking to started telling me about how much she loved threesomes, so I asked bluntly if she had sexual interactions with all the participants, or was it a V-some? She wasn't familiar with the term, and though I can't remember where I originally adopted it from, I will share it with you.
V-Some: A sexual encounter where two partners focus on the third partner, but do not have any sexual interest/encounters with each other. For example, a version of a three-some that you may be familiar with is a guy and two girls, with the two girls servicing him. This would be considered a "v-some", since the girls are not interacting with each other.
I don't use this term to deny anyone the right to brag about their three-some experiences, but when I hear the term "three-some" I will assume that all partners are interacting in a pleasurable sexual manner with each other and are not just focused on one person. If someone uses the term "v-some" it makes it clearer to me in the story who is having sex with whom.
A fun technicality term for your multiple sex partner needs