Bf wants me to beat/punish him...

My bf keeps asking me to tie him up and beat him, like punch really hard and stuff. He said it really turns him on, but I don't know if I could do that. Last night we were sort of wrestling in the kitchen and he had me pinned and I said I could totally knee him in the balls and win and he actually wanted me to. Knee him, that is, like full strength. Anyone with experience, advice please 🙏😖

He's spanked, choked, held me down when I've asked him to in the past and I want to fulfill his desires too but I'm naturally super submissive.