I tried different things, often starting the game from the very beginning and finding different "interesting things". Most likely this will not be new information for you, but still I will share, and it will be great if you share in response. So.
1 - If you call Laura a prostitute during the Halloween party, she will get very angry. After a day or two, she will find you herself and tell you her story. Usually, she only tells you about it if you have a good relationship, otherwise you can find out everything about her at once without wasting time developing relationships.
2 - If the relationship with the characters is not at a high level, you can get a random dialogue with them when trying to "just chat" provided that you saw them naked, or they saw you, and also if you gave them lacy underwear. This gives a good bonus to the relationship.
3 - There is a moment when you first try to enter Kitty's room after investing in a costume for Laura, they will be together in her room and will not let you in. If you have a good relationship with Kitty, she will let you into the room so that you appreciate Laura's outfit, and then they will escort you out. And if you have a very good relationship with both Kitty and Laura, then Laura will be naked, and you will also be escorted out, but if you immediately return to the room, you can try to persuade them to have a group sex.
4 - If during sex with a character, in one period of time she experiences a series of orgasms (somewhere from 7 to 10), then for the remaining time of sex you will get ahegao in any position, and not just during the "break" offer.
5 - If you don’t do any “sexual manipulations” with the character at all and manage to pump the relationship almost to the maximum, when she already confesses not in sympathy, but in love, and tells something intimate about herself, then the characters will say a “special” dialogue and offer to FINALLY have sex.
6 - Well, just observant players could notice that the characters are experienced in sex in their own way. And the more often you have a certain type of sex with them, the better they get at it, just like you learn to kiss them. For example, Kitty from the very beginning does not know how to deep blowjob, but if she does a regular one for a long time, then over time a deep one will open for her. And also all the characters give out special phrases if you are engaged in their favorite type of sex with them. For example, Laura just loves sex, Rogue just loves being touched, etc., but depending on how successful you and she are in certain types of sex, their interests may change.
I hope this was useful to someone, and I hope to learn something interesting about the game from you