I agree with Psythe. When writing erotic ryona, I like going the psychological route. I can enjoy it when taken to the extreme (e.g., failed mission, lasting public humiliation, and enslavement), and it's the kind of stuff I like to hunt for when looking for ryona.
As for physical damage, I usually don't like anything lasting. Permanent injury is a turn-off. However, I would not mind situations where brutal damage takes place in some fantasy setting where it is temporary:
- A fight in virtual reality
- A realm where healing magic will fully mend injuries or restore life
- A fantasy world that allows for "respawning," in some sense
In these kinds of situations, I can accept the concept of a grievous wound, and it doesn't mean the victim becomes crippled or killed. It also means that repeated fights or rematches are perfectly OK and natural :)
This resonates with me too.