Student blackmails teacher into publicly humiliating herself

A nosy student, spying on the teacher, takes photographs of her while masturbating, after which he blackmails her into humiliating herself by showing all the students her private parts. First, he forced her to come to class in a transparent blouse without a bra, then without panties under her skirt - so that everyone in the class could see her crotch, and then completely strip naked in front of him and his friend so that they could study her body. But in the end, the teacher found a way to get rid of the blackmailer.
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