ok so teasing and joking around can be fun and flirty but no matter how silly ur girl is being, NEVER EVER EVER CALL HER STUPID! or dumb or anything to do with that. cuz even if you say it completely jokingly, its still really hurtful. i know, i was just kidding around with this guy and he's like "man, ur so stupid" and he said it in a really nice joking voice but i was still really offended and it totally killed any chance of a good conversation.