"Smuggling tic tacs" is a euphemism used to describe a
lady's visibly erect nipples. It may be
cold, she may be horny, or she may genuinely be smuggling tic tacs.
Sometimes you may be in luck, and she may be smuggling a whole handful of tic tacs. This probably means that she has pierced nipples.
Every now and then you may be out of luck, and find that a
gentleman is also smuggling tic tacs. Best not to mention it to him though.