1) Perversion 40+ (both characters). 2A) With Cassiel, recieve a punish and a prank in her Waitress Job. 2B) With Saaphire, recieve a punish and a prank in her Nun Job. 3) After that, just go to sleep and you will recieve the quest.
just, try to find every H scene, complete the 2 specials (halloween and christmas), and that's it. Ohh! repeating H scenes will not rise their stats, unless the scene has added content the 2nd time (or 3rd or 4th... etc)