We say "knock on wood" to encourage a positive outcome or to discourage a negative one. Italians use the expression "tocca ferro" - touch iron - in a nearly equivalent way. Italian men will often touch their package as they say it, both reinforcing the performative power of the words and, I think, throwing in a little self-promotion.

A female Italian friend of mine will actually touch her breast when she says "tocca ferro", though I think she means it as a joke, as most women wouldn't really want an iron-hard chest. Any other Italian women out there doing this?