I don't know how Mac got the idea to do this pose or where he's seen it before, but it's probably something to do with having an older brother.

Having an almost-seven-year-old brother is also the reason I had to explain how Mac knows "California Gurls" by Katy Perry when I was at his conference last week.

"He has a really good ear," his teacher told me. "He sings songs he must know from the radio?" And immediately I pictured him doing his "bikinis on top" number during Montessori work cycle.