I want to say yes, but I'm not entirely sure. I have seen people doing adoptables where the lineart was incredibly realistic to that point, and as far as I know, the adoptables were allowed.

But I can't guarantee a yes, you might have to ask Eve.

Dash Attacked said:
I may need a second opinion from another moderator to back me up on this one, but I believe adding minute details of genetalia is fine. Obviously, doing something explicit/graphic is not, but it's pretty easy to tell when something is made for realism purposes vs NSFW purposes.

Considering the rule is "explicit sexuality," and minor details aren't really that explicit, I'd say they're fine.