Florida Principal Is Latest Educator to Allegedly Engage in Lewd Act With Student

There seems to be a rash of female educators accused of having sex with their underage students across the U.S. -- and there doesn't seem to be any end in sight.

In the latest case, Dr. Keiva Lark -- the assistant principal of Lake Marion Creek Middle School in Polk County, Florida -- was charged Thursday with lewd/lascivious conduct and lewd offense against a student by an authority figure.

According to police ... the 13-year-old student was sent to Lark's office after tossing crumpled-up paper across a classroom during an exam.

Cops say Lark ordered the boy -- who she allegedly called "Sexy Chocolate" -- to give her a foot massage, pointing out that he didn't have anything better to do with his hands at the moment.

Lark then allegedly took off her shoes and laid her legs across the boy's lap, commanding him to do as he's told.

Cops say a witness overheard Lark chastising the boy for falling down on the job before showing him how to do a proper foot rub ... by allegedly giving him a shoulder and arm massage.

The witness told police they heard Lark tell the boy to rub her as if he loved her ... and that she was teaching him these lessons for when he snags a girlfriend.

Days later, cops say, the witness reported the incident, and police launched the investigation on April 4. After her arrest, Lark was placed on administrative leave from the school.