The driver notices and asks them if they need to go to which they either shyly admit feeling silly they had to be asked like a child or shake their head and look even more like a child denying they need to go when they clearly do. Someone trying really hard not to grab their crotch because it’s embarrasing and makes it obvious they need to go, but at a bad spasm they’re forced to. Trying to squirm subtly because they’re right next to the driver, bouncing slightly in the seat, adjusting position, shaking their legs.
