Need a ban option

Alrighty! I recently played a game w/ a friend who went master yi and we did fairly nicely... (Was a massacre)... Anyways... After the game was over, the teemo that seemed pretty nice in all chat added me and then simply started flaming me. There was literally nothing I could do about this because we were already outside of the game, and he knew this... So anyways I tried making a few jokes with him and he eventually started making his own... And then he returned to flaming me before promptly removing me. So... I simply ask for a report option outside of the end of games. Thx. (Yes I have seen threads like this before and always wondered why they were a thing)