Help! Any experts or psychics? PLS READ OUR LECTURER MIND (4 the sake of the entire cl)!!!?

A LIBRA guy lecturer in 30s enjoys tapping girls on their head & shoulder when he feels she is good. At the sametime, he used to knock on girls head & poke their shoulders(& he said that is 2 make sure she is listening to him)He could praise a girl so well & suddenly give some sarcartics remarks 2 her. He often treats girls better than boys like as thought he is flirting with them.(But he says he is just being nice.)He is always showing exaggerate body language(even when he smile/talk)like he is trying to get attention.He tend to stare at us with a very cold& expression-less look(when he is waiting 4 an ans from his students)We all know that he is absolute normal in his mentality. But what is this guy lecturer thinking? Why is he behaving like this? From the view of a psychologist,what is his motive? We believe there must be a reason why he did all this! Anyone pls help!!