Naomi Jacobson in the title role of “Becoming Dr. Ruth” at Theater J through March 18. (Teresa Wood/Teresa Wood)
Theater critic

The sex talk is safe in “Becoming Dr. Ruth,” and don’t worry — there’s not much, even from the most benign voice ever to advise America to get naked and feel good about it. Mark St. Germain’s 2012 one-woman play is the backstory of how Karola Ruth Siegel escaped Nazi Germany as a young girl and somehow became celebrity sex therapist Ruth Westheimer.

The chronological script with Dr. Ruth directly addressing the audience is entirely too orthodox, but the production at Theater J has Naomi Jacobson in the title role, and a more adorable pistol you could not find. She’s got the voice: “communications” becomes “com-moon-ications” in the hearty stew of an accent that Ruth says is flavored with German, French, Hebrew and American.

More important, Jacobson’s got the Westheimer verve. She’s radiantly happy and healthy — a healer who has healed herself after losing her parents in the war. She’s healing again before our eyes: St. Germain’s play discovers Westheimer in her Manhattan apartment, packing up in 1997 after her third husband’s death.

“Oh!”, she says, noticing the audience. It’s a wooden excuse to begin explaining what’s going on and, well, why not tell the whole story of her life, since we’re here? But the intuitively funny Jacobson acts with the patented grandmotherly charm, fixing you with a friendly look and never missing one of the cheerful figure’s punchlines. She confides and natters around the stage, unpacking Westheimer’s life exactly as Dr. Ruth is trying to box it up and move on.

The set for Holly Twyford’s production is, in fact, a mountain of white packing boxes. This gives Jacobson lots to do as she climbs high to grab keepsakes or swings open small doors to reveal a dollhouse-size interiors. Paige Hathaway’s design includes historical projections by Sarah Tundermann, but they get a little lost against the clutter.

It’s interesting to learn that Westheimer — now 89 and scheduled to headline Theater J’s March 25 benefit — was placed with a horrible Swiss family after escaping Germany via the Kindertransport, and that she was a sniper for the Haganah during Israel’s establishment. Historical fiction is St. Germain’s go-to form: he’s written about everyone from Hemingway and Fitzgerald to Tammy Wynette, and “Freud’s Last Session” (at Theater J a few seasons back) led directly to this.

The information parade is just functional enough for Jacobson to jolt it alive. By the time Westheimer finally becomes Dr. Ruth and starts doling out advice over the radio, the disarmingly frank guidance has us laughing with relief, and Jacobson’s perky, no-nonsense turn has us believing all over again in this diminutive survivor’s singular star power.

Becoming Dr. Ruth, by Mark St. Germain. Directed by Holly Twyford. Lights, Colin K. Bills; costume design, Robert Croghan; sound design, Kenny Neal. About 90 minutes. Through March 18 at Theater J, in the Edlavitch D.C. Jewish Community Center, 1529 16th St. NW. Tickets $37-$69. Call 202-777-3210 or visit theaterj.org.