The young child makes her way to her parent's bedroom, hoping to find Mom or Dad in there but was not prepared to find her mother wearing nothing but a diaper (something she did not know adults could wear).

Flurry Heart: "knocks on door before opening it & seeing her mommy in a diaper i can't sleep, can i sle..."
Cadance: "Oh! Furry, dear, you surprised me."

btw, sorry about the little white dot on Cady's top lip but there was a little black smudge there & i clearly didn't cover it up well enough (even tho there's no black, there's still that dot but i suppose that's better than the former)