Sorry for commenting twice (the other is hidden), I messed up my first reply to you. x)

Belated reply, but, to answer you... I am not sure, actually! I will direct Nyght, the character owner, to this comment, to give you a better answer :)

That would be a tricky thing to explain. X3 They both have control over the shared body and can control their respective halves (and feel both halves as one). But there's also a bit of mental crossover and they can move and think as one entity. They are at the point of being individuals but also as one unified mind and they can flip-flop between the two states at will.

A bit of background on two of the images in the set kind of works to that. IN the 2nd image, Kyr and Saphrix are acting as one, a single expression and action across their face. Where-as in the 3rd image, Saphrix has decided to do a silly thing and take control of a small tendril hive within their body and poke one of its lengths out their mouth, which Kyr is reacting to the sudden tendril poking out with surpirse, and so you get a mixed silly/joyful expression from Saphrix while an Hey!/Surprise from Kyr.

This form is a step further than their conjoined form ( https://www.weasyl.com/submission/865739/ ) as caused by the merge orb Saphrix has. I am wanting to get an image done of them fully fused as a proper single being in the near future.