She has a cock

Looking up between your mother's legs you see that she has been experimenting on herself as well as you. She must have taken the same concoction that gave you your hermaphroditic traits. Between her legs, above her vulva is a large (and not just because you are shrunken) cock and average-sized balls. "As you can see, I used XD004 on myself." Your mother explained and grasped her already erect cock and fondled her balls. At 18cm, just over 7 inches it was bigger than you and wider still.

"What on Earth do you expect me to do with that?" You ask. "I don't think we need to run a test to find out that I can't take anything that big."