A high school Biology teacher reminds his class of tomorrow's final
exam.
 He tells the class there would be no excuse for not showing up, except
for
 serious injury, illness, or a death in the student's immediate family.

 A smart-ass jock in the back of the room asks, "What about extreme
 sexual exhaustion?"

 The entire class does its best to stifle their laughter and snickering.

 When silence is restored, the teacher smiles sympathetically at the
 student, shakes his head, and says, "Not an excuse. Write with your
 other hand.