This system is designed so that some special scenes unlock with characters you interact with most. You may choose to grind the trait asap, but that is your choice. You won't miss anything by having the Mega Slut trait at a low relationship level.
Let's say you like Lin the most. You'll naturally have sex with her a few times. Then you'll want to try new outfits, and new positions. This will naturally get you the trait.
I've also noticed some continuity issues. *SPOILERS* For instance, in the early-game, focusing on Emma's and Felicity's story, while ignoring Ashley's, later leads to the ability to c*m on Emma's chair in school, as if you'd never done so in her. In the late-game, Maria is there to help with Autumn's Capitol outfit, even if she's just been revealed to be a half-elf. Do let me know if you need some aid in development, pro bono. This game is well worth it.
