Reverse the situation and see if it still sounds funny
Instead of a 37 year old female teacher having sex with two 17 year old male students, make it a male teacher with female students. In that case, he'd be looking at a lot more than 45 days in jail. It really isn't funny about the sexual double standard that exists. The fact remains that a teacher is an adult in a position of trust with kids. As a former (and perhaps future) teacher, anyone who violates that trust is beneath contempt.