There were no requirements mentioned, but it was unclickable. I've had a few choices like this.
For example, second BJ from Keren, there was an option "teach her a lesson" or something like that.
Also, not walking to the bathroom in the club after Kara.
I dont remember every choice with this problem, still at the begining of the game, but I'm sure there were a few more.
Also, I have to ask, if I missed the chance to give Mori's sister my number because perv was too low - I will have no other chances?