"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.