Your teacher and you have a great ‘friendship’ as you call it.one day he helps you with your homework what turns into smaltalk.what did you do today,how did you sleep yadda yadda yadda

Then you ask him why he became a teacher.he answers very ironic and jokingly

“Because i like highschool girls,thats why!”

It was obviously a joke.but you didnt understand it as a joke