I narrow it down like this.
Love Interest "Important Characters" - Relationship and Sex based on mutual feelings.
Lust-Driven Characters - Sexual encounters based on lust.
- Alyssa
- Zac
- Julie
- Aiden
- etc...
Filthy Point Fillers - To facilitate the desire and frustration within Sophia and lack of sex with Liam based on small encounters (one, two, or three scenes, they no longer have a part). May or May not have sex scenes.
- Museum Guys
- Gym Personal
- Side Jobs
- Movers
- etc...
Of course, the sexual encounter will be based on if L&P gets that far or not outside of Liam.