Say, "Ummmmmm...okay?" and hope he wasn't trying to enchant me.
WWYDI a young Dufflepud asked you to help him find his parents?
help...
WWYDI Aslan tossed your house walls and roof aside, leaving your bedroom (and yourself ill in bed) fully exposed to the great outdoors?
Be confused.
WWYDI you were stranded on Coriakin's Island with the Dufflepuds?
Swear that the new Narnia villain was the Mary-Sue.
WWYDI your best friend suddenly revealed that s/he's actually a half-dwarf?
"What? Then how come you're almost my height?"
WWYDI your tutor (NOT your mom, if you're homeschooled) told you your uncle wanted to kill you?
Freak out.
WWYDI you saw an old newspaper article telling about a London train crash in 1949?
Not accept.
WWYDI you were invited to Harfang?
Ask them nicely to get off.
WWYDI Edmund asked your opinion about building decent roads?
Accept, and freak out!
WWYDI Coriakin asked you to help him write a book?