Also I believe I found a trick to make punches realistic.
Add MMA to the pormpt

IMAGE
Extremely high definition photo of a woman in a boxing gym, standing among a row of punching bags, taking the place of one of them. Her hands are raised up and tied to the ceiling with chains, restrained with handcuffs, armpits visible, sweating profusely. She wears a sport shirt with the text "Human punching bag" printed on it, midriff exposed. She looks sensual and eagerly awaiting to be beaten up as a punching bag. Indoors, bokeh, high quality, extremely detailed.

VIDEO
GIrl is suspended by the chained handcuffs. A guy walks in and starts punching her belly and tits., like if she was a punching bag.
Pain, bruises , MMA, ,blood,