Well, I think I discovered how to get the 3some scenes consistently now...
(There are only four scenes, and you can only access those during the interaction, which is pretty disappointing, to be honest.)
Things to Keep in Mind:
Fewer characters on the map is better –(Since they want to unalive themselves and break up whenever there are too many characters interacting with you, and you cannot even walk without being interrupted) It’s nearly impossible to trigger the scenes without setting up the stage properly. Keep only 3–4 characters max on the map to force interactions. Most H scrambles fail because the characters have a bad relationship with each other, a character either calls you boring for interrupting the scene or the male character becomes indecisive when this happens. (So it's easier to mange fewer characters)
Properly setting up the characters – You’ll need to adjust their traits, sexuality, personality, and sexual tendencies. I recommend the following traits: Bisexual, Carnivore (mandatory), Calm, and Lustful. After that, interact with each character to raise their affinity. Ideally, they should have either the "Lovebirds" status or at least very high affinity—both general and sexual. To make this easier, take control of the characters, have them hook up, and make sure they all start dating each other.
Use the balance menu in configuration – For some reason, characters start hating each other way too fast. To counter this, tweak the settings by increasing love and affinity gain while reducing hate. Also, hide the "Cheater" and "Homewrecker" traits/status effects, as they make this process impossible. Finally, use the menu options to put characters into heat if you don’t want to grind too much.
That is all I could find, please let me know if there is an easier way cuz, I had to experiment with all this sh*t to make it work consistently...