Instead of a dom texting you teasing messages while in class, what if they tease you in person while in class?
A dom and sub having the same class, and every once in a while the sub will look over at their dom, and the dom will wink at them or do something small that'll drive the sub nuts. The dom will wink, pull on the collar of their shirt (or a chain necklace), bite their lip, or look the sub up and down.. These things drive the sub crazy, and the sub ends up asking to go to the bathroom to release..
