Iv'e put 'normal' in inveted commas, IYSWIM.
Bought ds a whoopee cushion for £1.50 and he loves it, has been farting his way round the living room, laughing and signing 'fart!fart!'
Just like your average 4 yr old boy. Really nice to see him do something he doesn't need explained, or wants to do differently to everyone else.