The fig sign is when you make a fist with your hand and stick your thumb between your first and second fingers. It looks like you're giving someone a special kind of handshake!
Some people use the fig sign to mean good luck or good fortune, especially in Mediterranean countries where it is a common gesture. In some places, it's even used to ward off evil spirits or bad luck.
But be careful! In other places, like in America or the UK, the fig sign can be considered rude or offensive. It's important to be aware of cultural differences and to always be respectful of others.