Our thanks to John for this. An extract:
The LegalFling website is crystal clear that anyone has the right to change their mind at any time.
“‘No’ means ‘no’ at any time. Being passed out means ‘no’ at any time,” the FAQ page states.
“This is explicitly described in the agreement. Additionally, you can withdraw consent going forward through the LegalFling app with a single click.” All you need to do in the thick of the action is take a deep breath, open the app and adjust the settings to tell your sex partner you are no longer comfortable with something.