Hormones are needed for transformations . You'll need to have a 75% or more feminine hormone for transformation to occur

Class Drops:

• After Fem 301, you will get them each time you go to class.
• After Sissy School class is over, take the elevator to the White Room in the school.

Missy's Jobs:

• Running errands - if you get the chemist you can steal some pills
• Cleaning the bathroom they can appear at random

Buying from Spanky:

• Talk to Spanky at the Diner
• Talk to Spanky in the Pink Room while he is working as a waitress.

Cult

• Once you declare yourself a Sissy you'll receive them each morning.