I really enjoy how once you play D&D with someone long enough, you learn exactly how they role dice. Some of my favorites are:
-Pinching the die and dropping it from high up.
-Jiggling it on a flat palm, letting it slide onto the table, then darting both hands under the table as if to stop them self from interfering with the result.
-Shaking it between two palms as though they’re praying before rolling.
-Shaking it in a closed fist at head height before rolling.
-Unleashing it into the air with a wrist flick, giving it backspin.
-Shaking and then slamming it on the table under your hand so there’s no way they’re going off the table.
-Slowly tilting their hand sideways like (old) Bilbo dropping the Ring.
So, I like to imagine Sonny's dad walked out on him and his mom when he was super young. So Sonny's grown up with Usnavi being like dad to him. So when they win the lotto, all of a sudden this dickweed emerges from no where and tries to get close to Sonny (just for the money) and 'Navi is NOT having it