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The thing is, Frank doesn't actually mean to become a babysitter. At first, he regards it as a kind of horrific accident that's somehow befallen him through no fault of his own. When his mom first mentions it, he's sprawled on the couch doing his best impression of an extremely sober person who was absolutely not about to jack off before passing out for the night. "The Ashers need a sitter for Friday night," she says. "I told them you were free." Frank lets that sentence slop around his brain until he's sure it doesn't contain the words "drinking" or "pot" in conjunction with "have you" and "been", then he makes a vague noise of acquiescence and promptly forgets all about the whole thing. Alternatively, the one where there is absolutely no shame in asking an eight-year-old girl for relationship advice.