She starts off by proving that John shops in the Junior Miss section.
Panel 1: We start off by watching him ask Elly, who's (of course) holding Lizzie, what she thinks of the macho shirt he just bought.
Panel 2: Realizing that her husband just bought a woman's V-neck sweater, she asks him what's so macho about it.
Panel 3: He replies by telling her that she can see his (one strand of) chest hair. She can also see that he's suddenly more curvaceous than she is.
Panel 4: She muses that she'd thought it had fallen out. This is because he's starting to look more feminine than she is and it amuses her.
Summary: This is probably going to end up with John going to ever-more ridiculous lengths to prove that he's a he-man and failing ludicrously.