naughty Pasty, the clue was net yet open :-0
Ass is correct.
Definition = bottom
1st letters (from tops)of 'American standard size'
Americans (mainly tourists) are renowned for their lardarses.
Yes Ass was correct.
hey, can't believe anyone could take real offence here, it is nothing more than postcard humour.
i made it up almost as i was typing so might have censured it (although i doubt it).