i dont know what tells u happen to give off but sometimes when i have either a monster or total air, if the money happens to be a serious amount of cash, i sometimes cant help but smile or grin, i can try and hold it but what would then happen is the end of my lips will curl up slightly and if its a long staredown i just burst out laughing or do a stymied (used that word wrong) type of laugh(more like a giggle).

anyway what helps me from smiling is gritting my teeth, ( i find this helps me limit my facial expression) and stops me from letting the occasional grin sneak out.

now i alwasy stay stonecold and grit my teeth whenever i have made a bet for someone to call weather i have it or not