Chandler's teacher's wife teaches next door to their classroom, and is famous for shoving cupcakes in the face of the birthday kid. They go to her, begging to have her shove their cupcake in their face. (I don't get it either, that's just what I'm told). Kind of like the music teacher at Gabe's school, who gets a cupcake from every birthday kid simply because he has a reputation for eating the cupcake in one bite and every kid wants to see that!)