this photo came up on a goole image search for "freak dancing"...

LEMOORE, Calif. - Fed up with students' racy moves, a principal at a California high school has taken the unusual step of canceling the rest of this year's school dances.
Principal Jim Bennett of Lemoore Union High School said he warned students at a winter formal dance last month to either quit dirty dancing or face the possibility of not dancing at all.
But he said the students continued "freak dancing," a form of sexually suggestive dancing that involves grinding the hips and pelvic area.