This is a Sixties Original Hippie Psychedelic Button "Pussy Is Better Than Hamburger".  It is a sex pinback from the free Love era promoting a vegetarian vegan lifestyle. Each one of these buttons was made differently. 

MANY OF THE BUTTONS I AM LISTING ARE ABOUT 40-50 YEARS OLD AND
THE SUBJECTS COVER: THE VIETNAM WAR, SEX, HUMOR, ROCK MUSIC, LSD, MARIJUANA (POT), NUDITY, PEACE, DRUGS, EDUCATION, AND POLITICAL ONES LIKE SNOOPY FOR PRESIDENT.

DESCRIPTION: Original hippie pinback

CONDITION: UNUSED -see all photos (SEE PHOTO).

BUTTON MEASURES 1 1/4"