The ability to grow to denote that genitals are excited.
Color matching. Which I imagine will be the most complicated because most companies give generic 5 colors that are passable but not realistic for everyone.
3D balls are a must.
A fair stp option for those whom happen to a urethra that is set farther back(I mean 3-5inches from the urethra to the mounds).
If possible a merkin option that can withstand the test of time. Especially for those who have coarser hair.
If possible the option to ejackulation.
