Another case of adult words put into a kid context here. Not a bad joke either, I'd say.
Let's take a moment to compare this with the first strip:
It's been around for just under five months at this point, but already the characters show considerable changes. We're immersed in the early days of the strip so far in this blog, but although there is a winning style in these early strips, it really doesn't last long. Already the character's eyes have enlarged into ovals, their hair has filled out, the faces are more expressive and the lines are darker. Character heads are beginning to vertically expand into the near-circles we knew for over forty-five years of the strip's history.
Three years after the strip's debut, the original style will be almost completely gone: