J - Joking around with you:
It's hard to tell when Shinsou is joking with you, because he always has the same look on his face; he only reveals a smirk when you give him the reaction he wants to something he says or does. In certain moments, after there's a huge amount of trust between you, he'll sometimes use his quirk to take control of you threaten to make you eat something disgusting (he'll never go too far, and he won't do it unless he knows you trust him enough to the point you know he'd never hurt you).
W - Waking up to you:
Mornings feel more peaceful when he gets to wake up next to you, perhaps offering a little more reason for him to open his eyes in the morning. He's still groggy, and sometimes just lays in bed, an arm thrown over you as he laments he can't just stay in bed with you all day.