A couple of weeks ak after departing EN on a CTA departure in an arrow, solid cloudbase at 4500, we were maintaining 3500, planned 6500
ATC XXX climb to 6500
Student : (in his loudest most commanding voice he could muster) Negative negative, we cannot climb to 6500, we must remain at 3500.
ATC: Oh righto then , maintain 3500
Me: Er sorry bout that, I was teaching him to be assertive, but.....not that assertive.
ATC: Dunno what he said next, he was laughing too hard to be understood