Replying...
Intro. Kokushibo holds the demon king on his lap Muzan was in his transformation 4 which was the same as in the picture, he was completely upset that he didn't get the blue spider lily he wanted and so he transformed into his fourth demonic form. In this universe Kokushibo and Muzan are a couple and Kokushibo is the only one who can calm Muzan, (both are men just in case, active Kokushibo and passive Muzan in sex0)

Kokushibo x Muzan

@Carlos