He pulled a Mathis
It is in reference to Otis Mathis, Chairman of the Detroit School Board, who was fondling his private parts for 20 minutes and then unzipped his pants while ejaculating in his "hanker'chief" while meeting with the Superintendent Teresa Gueyser.
"He pulled a Mathis" wile in the classrooom despite being ill discipline to maintain a focus on education and was anxious about taking a test he knew he would fail.