It's actually not even a
requirement to have a small penis to be considered a trap in this game at all. (Or at all in general, in my super highly unpopular opinion)
You just need to have the corresponding bits and facial femininity for the game to recognize you as one in the code.
From the wiki:
Femboy/Trap
- Steele is androgynous or feminine, has at least one penis and breasts smaller than C cup.
The dicksize really doesn't matter at all, it goes off "what parts you have in general + facial femininity".
I played girly boys with 12 inchers that can still get trap exclusive scenes because a tiny penis is not even a requirement to even be a trap in this game, that's just what the stupid trope has you believe.
Especially considering even a 0.5 dick is still usable in some scenes because people don't care to go that low in terms of accounting for them.