It is certainly possible, though the teenagers on social media have discredited it to a degree, and made productive discourse a bit difficult. The whole topic is rife with broken people desperate for love and attention, as well as power imbalances in favor of the entities. It may be one of highest forms of commitment to an entity, if you're into that sort of thing. Provided of course the entity is interested. This is very, very advanced stuff, best left to folks with 10 years or more of experience with the entity. In my opinion it is never, ever, actually necessary, even if an entity brings it up. I also see it fitting into a religious approach better than a magickal one, though it would still be possible. And no matter what an entity might tell someone, they are never, ever, going to be monogamous with an incarnate human.
It's not my thing, and I doubt it will ever be. When people ask me about it, I usually try to talk them out of it, which may or may not endear me to the entities, and is largely pointless anyhow. People will do as they will.