At a certain point in the game your character will say something like "You aren't sure if you can cum without a cock anymore." at which point you can only lower arousal by having sex with a character, showering, or fapping to sissy hypno.
In my playtesting today I did notice there are some problems with that first solution (some sex scenes with characters either didn't have something that lowered your arousal to 0 in the original version or im just an idiot who somehow missed them) so id recommend either showering or fapping to sissy hypno for the time being. Just keep in mind not
all sex scenes will lower your arousal to 0 just those that your character actually finishes during.
If all goes well ill be posting a mini update here later tonight. So far ive done some bug fixing and ive implemented the grade system fully (im actually in the middle of play testing to make sure its not a total pain rn) and if i have time that update might even include a new scene or two
Hope this helps