Human servant Yuji who has got an oral fixation on sukuna’s cocks and he sneaks into his masters bedroom to suck on them while he sleeps. It’s not uncommon for sukuna to wake up to Yuji nursing on his dick, covered in cum and eager to lick the mess up. The only reason why Yuji gets away with the noncon somno is because he registers so much of a non threat to suku’s instincts.

Sukuna’s ego enjoys how needy yuji gets over his dicks, which is why he keeps Yuji around, but he does put Yuji in a gag if he misbehaves and makes him watch as a whore gets to suck him off instead. They usually choke and die on the dick but so minor character death that it doesn’t matter.

Yuji’s got no gag reflex because he practiced with his own fingers and sukuna’s dicks while he slept.