Best friend/housemate hits my balls to get her way

So I am a gay guy (25M) and have been living with my best friend (26F) for a few years now. We love each other to death, but she is a bitch and a half.

Anyway, she knows that I am on the submissive side, and for the past year she has been basically been hitting me in the crotch whenever it suits her. We have this kind of silent understanding that I kind of like to be hit in the balls overall, and she knows that I have had bf’s that liked to do that to me and I think this gave her the idea. That said I always get very mad at her every time she does it, but we always laugh it off afterwards.

For instance the other day a disagreement about what movie we would watch and by the time I try to change the channel on the TV she gave me a full on punch in the nuts in order to grab the remote.

I think the funniest -and most painful- incident was last summer. We went with to a bar and there was a groups of guys sitting next to us and we started chatting with them. One of them was quite hot and he seemed to be talking a lot more to us than the rest. At some point his friends left but he stayed behind with us. My friend obviously fancied him and was overjoyed at the moment. The thing is the guy was gay and he became much more friendly towards me after the others left, to the point that we kissed after a while.

I could see my friend fuming. On our Uber ride home she was very mad about why all the nice guys are gay etc, and that she wanted him and whatever. By the time we enter home the guy texted me and I was quite grinning, and then she said I’ll give you something to laugh about and she gave me a full knee in the nuts. I fell to the floor from the pain and the dialog that entailed is the funniest, we still laugh about it.

(me)

\-you are such a loser bitch

\-well you got the guy but I smashed your nuts

\-well guess what bitch, I am a bottom, I can still have the guy.

Despite being mad at each other we kind of laughing hysterically at the situation after this. Long story short my balls were bruised the next day, and to this day I still flinch when she angrily approaches me.