It does as intended

Penny doses John with the "medicine" over the week she notices a change in John's body and body language, over the week your muscle shrink and soon you look smaller and skinnier than your strongly built father Ryan, and soon your old pants can't even make out the shape of your tiny cock!

as Penny realizes that she needs to check to make sure the medication turned your penis into a micropenis and the only way she can think of making sure is checking your penis

When she does she sees your small 9 inch cock has shrunk to 3 inches and is now only needs two fingers to jerk

On the inside she is bursting with excitement she had succeed in making sure you could never be a real man.

as Penny sees this her pussy begins moistening and she begins to drool over your new place in life as a weak cuckolded wimp