A Round-Heeled Woman, Riverside Studios

Sharon Gless is best known for her role as Detective Christine Cagney in Cagney & Lacey, and then to another generation in the American version of Queer as Folk and currently in the drama Burn Notice.

A Round-Heeled Woman is an adaptation of Jane Juska’s bestselling book of the same name, subtitled My Late-Life Adventures in Sex and Romance, which chronicles the sexual encounters the retired high-school English teacher and Anthony Trollope obsessive had after placing a personal ad in The New York Review of Books: “Before I turn 67 - next March - I would like to have a lot of sex with a man I like. If you want to talk first, Trollope works for me.” Juska received 63 replies, from men aged between 32 and 84, and now Jane Prowse (who also directs) has adapted it for the stage. A round-heeled woman, by the way, is a Victorian phrase for a prostitute: their heels would be rounded down by walking on cobbles.

It's rather affecting to see mature libidos treated with respect

The play opens with Gless having phone sex with one of her admirers. It's a brave directorial move as at least some of the audience may squirm at this; porn aficionados may like it, but watching someone simulate a masturbatory orgasm on stage will never be a comfortable experience – do it too well and it feels like an intrusion, do it badly and it's risible. But Gless – not for the first time in a play that occasionally struggles to transcend its subject matter – pulls it off (sorry) as she assures her lover she is alone, telling him she would never do this in front of an audience. She leaps off the bed, gives the audience a knowing look – Gless's comic timing is, as ever, impeccable - and addresses them directly to start the story.

Juska tells us how with her friends (played by Jane Bertish and Beth Cordingly) she decided which of her respondents she decided to meet - one of them mistook Trollope for trollop, another slept with her simply to prove he still could at the age of 82, while another was still playing the field in his sixties. We also hear snippets from Juska's sexually repressed childhood and how books became her passion after she divorced, explaining why she hasn't had a lover in more than 30 years.

Prowse's play is mostly schematic, save the occasional flashback in the telling of Juska's broken relationship with her only child, Andy, and the scenes in which the Trollope heroine that she runs to in moments of doubt, in a “what would Miss Mackenzie do?” kind of way, appears. These scenes are well integrated and deliver a few laughs of their own. As Miss M is considering whether to accept her cousin's marriage proposal, Gless barks: “You're on page 247 of 249 pages. Your options are limited.”

The supporting cast of five – for this is, with absolutely no disrespect to them, a star vehicle – play multiple roles and are uniformly terrific as they paint the light and shade in Juska's descriptions of her encounters, some comic, some troubling and some heartwarming, particularly her assignations with Graham (Michael Thomson), who also pointedly (calling Dr Freud) and disconcertingly plays both Andy and Miss Mackenzie's suitor. Barry McCarthy and Neil McCaul play Juska's various lovers and her long-dead father.

Despite the occasional line for the feeble-minded – we don't need to be told that Trollope was a great Victorian novelist, for instance – and a cringe-making schmaltzy moment of mother-son reconciliation, Prowse's script mostly avoids Hollywood dross and it's rather affecting to see mature libidos treated with respect, compassion and a nicely comic touch.

• A Round-Heeled Woman is at Riverside Studios, London W6 until 20 November