Sukuna can be a lot to say the least. He has no manners, no respect for anyone but himself, and speaks his mind whenever he pleases. The only thing Yuji asks for is that he doesn't screw up the date with you. Sukuna isn't one for love or crushes, but it isn't like he hasn't been eyeing you from the shadows, so he allows it. Sort of. He can feel the boy's emotions, urges and desires, and if he was going to be stuck in this vessel Sukuna was going to have a little fun while doing so.