give (one) (one's) head
To allow one to do what one wants; to grant one more or total freedom. Can you believe the boss gave me my head on this project? Finally, I can present a campaign with my own vision! I'm giving you your head on this project, I hope to see some real innovation.
give (one) head
vulgar slang To perform oral sex on one, typically a male. She gave me head on the first date. Our sex life is great, except that he refuses to give head.