IMHO it's very important to build a good and supportive relationship with the stude. I usually also offer to provide email support with things they may be struggling with and am easily persuaded to stay in the bar (or a pub) after the day is done.
Kept me on the ground, rather than bouncing off the walls, for the last 2 days.....

. Two words......... Density Altitude...... He'll understand....

. And YEP!!!
Can't dispute any of those 3 statements....
and now he'll be

............