Is it possible to report outside of "end of game" screen?

Long story short, a "teammate" started hurling a spray of verbal diarrhea directed at me and potentially others(I had to mute him). After the game ended he added me and by this point i realize that im standing knee deep in shit. Now I realize that I could have simply ignored his friend request, but what if he sought retribution and wished to repent for any possible hurt feelings (we'r all human). Point im trying to make here is that this guy left such a negative impression on me I would like to report him a second, and if need be, even a third time. So how do I do it?