"When he does his nose lights up and wakes all the other reindeer," I tell them. "Then Dancer starts dancing, and Prancer starts prancing and all the other reindeer start playing around and making a noise, and Mrs Claus has to send me downstairs to make them quieten down so that we can get some sleep."
I've even invented a bit of Santa lore that I reveal as a whispered 'secret': Mrs Claus's first name is Sandra, Sandra Claus.
As well as youngsters there is a steady parade of teenagers and adults turning up for their traditional family Santa photos. Some teens – particularly girls – have their photos taken under protest and getting them to smile rather than pout can be as hard as getting a grin from a baby. Most, however, take it in the spirit in which it's meant and have a lot of fun.
The youngest member of one set of three siblings – a sister and two brothers – was 28 years old and they had been having the Santa photo taken since birth. Another young bloke in his thirties had his photo with me to send home to his Mum on the first Christmas he hadn't been able to get home to celebrate with her.
Adults' almost instinctive reactions to the red suit are informative. Although they know full well that I'm only a stranger in a costume, I must remind them of the simpler and happier times of their childhoods and they invariably wave and greet me with "Hello Santa" or "Merry Christmas, Santa", as if I'm an old friend.
And I suppose I am. An old friend who comes every Christmas to remind people of the Christmas Spirit and inspire them to be light-hearted and kind to one another. Merry Christmas, everybody!