There was a time in the 1980s when Dr. Ruth Westheimer, petite sex guru and irrepressible advocate of democratized pleasure, seemed to be everywhere. In bookstores and on the radio, or perched alongside a squirming Johnny Carson or David Letterman, she thrust the female orgasm to center stage while reassuring men that its achievement didn’t require supersized equipment.

It’s hard to explain how revolutionary her humor, candor and sexual explicitness seemed for the time. Nothing was off the table: when H.I.V./AIDS and homosexuality were barely acknowledged publicly, she was there with fact-based advice and warm encouragement. Now the woman who just wants everyone to feel good gets an equally flushed tribute in “Ask Dr. Ruth,” Ryan White’s rose-tinted overview of a remarkable life.