I tried so hard not to laugh...

I team teach a special ed inclusion class one of my periods. The class is split pretty much 50/50 between SpEd and GenEd kids, so there are two teachers in the room. My coteacher has been at this game for 20+ years, so she's got the no-nonsense bit down pat. This particular day, she was shuffling across the classroom to go deal with a boy who was making weird noises and trying to get his classmates' attention.

Teacher: Ladies and gentlemen, we are taking a test, it needs to be quiet in here! *walks directly behind the child*
Boy: *fart noise* *shocked face* Mrs. (teacher)!!!

The whole class erupted in giggles. I followed suit. Because, seriously....it was funny. But then the kids noticed I was laughing, and that just made them laugh harder. Oh well.