Is someone you clearly aren't dating in real life and you clearly aren't dating to help you in math class (for you are definitely the intelligent one of the two). A math boyfriend is someone you are using just to give you the much needed attention you are lacking and to give you the idea of actually being in a relationship, in which there is seriously no commitment. Basically making you a needy douche.

when you've done something so cringe you can't stop replaying it in your head and it stops you from getting on with your every day life