First Years
Yuji Itadori
Ok, let's get this straight. You guys were doing this before you were together. Like all the time. Everyone thought you were a thing before then because half of the time you were halfway up his chest. He likes to spin around to make you hold him tighter and because he likes to hear you scream in surprise.
Megumi Fushiguro
Megumi is usually not a hugger but whenever he wants one, he will need it. He wont talk at all, he'll just hold you like a body pillow.
Second Years
Toge Inumaki
Once he realises that you don't care about his marking, he'll almost always have his face covering off when you're alone. He really likes doing this because it makes you laugh. He'd also tickle you.
I also highly headcanon that Toge LOVES loves loves laying on your thighs. He just loves everything about them. Big, small, muscular, soft, it doesn't matter as long as he gets a place to lay his head.
Professionals
Kento Nanami
After a long day at work, all Nanami looks forward to is seeing you. He'll come home stiff and exhausted, looking for refuge in your arms. He'll just slump onto you before asking how your day went.
Satoru Gojo
It just gives me Gojo vibes. He's definitely one to press his face into your chest.
Cursed spirits
Mahito
He doesn't need to sleep, but he will close his eyes the whole night and just think about the feeling of you pressed against him. If it was possible he'd press you even closer to him, so he could feel your heart and soul against his chest.
Sukuna
Every once in a while, he'll be in a very good mood, and that comes with increased affection. When no one's looking, he'll get soft. He'll always deny it to anyone though.
Choso
He doesn't need to sleep so he just kind of stays really still so he doesn't wake you up and plays with your hair or just watches you sleep the whole night. Not in a creepy way though. He's told you he does it.
Curse Users
Suguru Geto
I can totally see him doing this in his cult. He's either doing his signature pose or laying in your lap.
Special cases
Junpei Yoshino
Ok, he really loves laying on your chest. I mean, it's comfy, he can feel your heartbeat and it means you can run your hands through his hair.