Nail Polish
It's an old habit and one he'd hate for anyone to find out about.
It's his sisters fault really.
When they were kids she used to glue little gold stars on his nails before a big game.
But that was when she was three.
As she grew older she began painting his nails different colors before a game.
Until when she was ten and he was thirteen and he decided to put his foot down.
"Lindsay you need to stop painting my nails!"
"But Mick it's good luck!"
"No it's not!"
"Have you ever lost a game?"
"No but-"
"No buts! At the very least let me paint your pinky nail."
So he did.
And when he went to Anubis and she wasn't around to do it for him he painted it on his own.
And he still hasn't lost a single game.