Piger is a slang word which means “to understand”.
J’ai rien pigé à ce qu’il a dit.
I understood nothing about what he said.
Je fais ce que je veux, tu piges ?
I do what I want, got it?
Note that in Canada, piger means “to pick”, “to take”. I remembered that my mother used to play a computer version of Scrabble produced (or translated) in Québec which informed us that “la dernière lettre a été pigée” (“the last letter has been picked”). This is a normal sentence for French Canadians, but in France it probably won’t be understood.
Listen to the examples: