Finish up with the school's females

You get the basketball girl shrunk down and jarred for safekeeping, then move on.

After another while you're finally stripping the last woman: A beautiful purple-pink professor with shoulder-length indigo hair. She struggles more aggressively than the average girl, trying to get a few attack spells off at you before you pin her over your knee and start shredding her clothes. In seconds she's down to her shoes, a white bra, and a red thong.

"Miss Pyrrah is butt-flossing!" shouts a gleeful voice in the back, getting a big laugh.

"Boys, avert your eyes!" she shouts. "A woman's body is her own private--"

You give her a small swat on the ass. "No lectures from the eye-candy."

"I am not--"

*Swat* "No lectures from the eye-candy! Your students are trying to enjoy your body!"

You rip off her underwear before she can object any further, exposing a pair of C-cup breasts and a stunning seat cushion. She screams and kicks her legs furiously, but succeeds only in causing her buttocks to jiggle for the crowd. You're not quite ready to let her up off your lap.

"You all have been a great audience!" you announce. "And your girls were very fun to strip! I almost wish I didn't have to leave you now, but as a final parting gift, I thought I would enchant the lovely Miss Pyrrah here with a little hex of my invention. She will be unable to use magic or dress herself until such a time as she forcibly strips another girl! At that point, the curse will transfer to the girl she strips!"

Pyrrah looks back at you with wide eyes seconds before you bring your palm down on her ass, spanking the curse into place.