after professor john michael bailey's sexuality class, students observed a live demonstration. a man, a woman and a motorized device. john marcus was one of the demonstrators, along with his fianc fiancee. they also brought along whips, paddles, and a clown wig. >> the students were smart. they asked intelligent questions. >> we were there to give more information. not just what the school has to show you on file. >> reporter: the demonstration happened half class. the students were warned repeatedly it was coming and not required to stay. but it has sparked debate. >> i'm glad i didn't see it. it's a little too explicit for me. >> dr. michael bailey is one of our best professors here. >> reporter: in a statement, the professor said, the decision to say yes reflected my inability to come up with a legitimate reason why students should not be able to watch such a demonstration. after defending the professor, northwestern says it is now investigating the matter. the university president saying, i simply do not believe this was appropriate, necessary, or in keeping with northweste