After my parents got divorced in the early '80s, my dad used to leave his copy of The Joy of Sex lying around on the coffee table, which was quite educational for a 12-year-old. There were always Playboy magazines lying around throughout my childhood, and he kept the kinkier stuff in the bottom drawer of his dresser.

Library-wise, Erica Jong was probably the most reliable author I discovered as a teen for reading about people having sex.