"There's your fresh air!"

Mommy told Nick that while he was resting, she might take a walk to get some fresh air. Now, Nick is generally not ammenable to Mommy departing the premises in any fashion whatsoever. So, as amusing as it was, it was hardly suprising for him to raise his tail in Mommy's general direction and call upon his skunk-like talent to fart on demand and then provide the punchline quoted above. No mistake; that is how he felt about that.