Onto personal wishes, much less likely to be hotfixed in: I saw in previous art you've done spirits with equine penises. Is that an option we can get in customization for males?
And, on a likely much more distant note, perhaps a slider specific for dick size (And possibly breast size). That's the sort of thing people like to fiddle around with to-taste, and a linear scale sliding back and forth is probably not too difficult to make a simple implementation for.