only reason I can think of is
practice ...
he'll be a legend at work - and is still probably fondly remembered down at the local.
eh jack lad - do you remember when he cleared the whole snug on just two peanuts and a pork scratching? ... aye! ... even 't jack russell were sick.
however mortified you are ... and he appears to be ... he's proudly chuckling inside
just wait 'till he starts filling the biscuit barrel when the parents come round
it's a sort of aliens vs predator thing ...