Annoying as hell new term biology teacher

Dude constantly bugs me about covering my face and leaning back in my chair. What even is the problem with leaning back in my chair? I'm listening all the same. In fact, I'm probably listening more if I'm relaxed in class. Can I not be comfortable and listening at the same time?

Actual monologue my teacher gave me:

(notices me lying back in my chair)

T: Right, <name>, if you don't get your head up you're going to have problems in the exam.

Me: Yeah, don't worry-

T: No, it's not me that's worrying, it's you that should be worrying, (etc etc etc whatever lecture)

Like dude. Stop tryharding. Nobody cares.