"When a character asks their partner to stop, protests, struggles or otherwise withdraws consent midway through sexual activity if they had not done so before."

This tag would be useful for two reasons:

• This kind of scenario in porn is hot.
• It presents an educational opportunity: if other participants ignore the unconsenting character's protests, then this tag will imply "rape". This is a sadly common scenario in the real world and describing it here could help make the moral boundaries clearer for users.