While he believes his wife to be physically strained from an excess of milk that is insufficient to feed their child, Catherine is sexually dissatisfied with her husband, who is fascinated by electricity and struggles with intimacy.
In late November, the doctor brings in a new patient, Sabrina Daldry, and her husband, Dick, who has grown frustrated with the inhibitions arising from his wife's hysteria.
Catherine observes her feeding the baby and reacts emotionally; she tries to explain to her husband about her insecurities of motherhood, but Dr. Givings is more interested in medicating Mrs. Daldry with another round of electrical therapy in the next room.
Elizabeth prepares to return home to her own family and is asked by Catherine if she plans to have more children, before divulging her own personal fears of childbirth and the great pain she felt when Letitia first tried to nurse off of her.
The doctor resolves to treat her with the vibrator, much to his wife's chagrin, but when Annie's absence gives her trouble reaching a paroxysm once again, he successfully uses what he refers to as "vulvular massage" in addition to the instrument.
Dr. Givings unveils his latest invention, specifically designed to medicate hysteria in a man; a device that inserts into the anus, which he refers to as the "Chattanooga Vibrator".
She then converses with Sabrina about continuing to explore the vibrator on their own accord behind her husband's back, but their plans are interrupted by the doctor, who brings her into the operating theater for therapy.
Their conversation quickly turns to an argument as Catherine claims she is mentally unwell and begs to be treated in the next room, and Dr. Givings postulates it is because of the excess of milk.
In the operating theater, Dr. Givings attempts to conduct therapy with his wife as he would with any other patient, but the experiment quickly turns sexual as Catherine insists they kiss while he holds the instrument to her person.
She flees the house in a fury while Dr. Givings, in a creative stir, summons Annie to help him draft plans for a vibrator made of water, designed to treat more excitable patients such as his wife.
Mr. Irving, embarrassed, makes his exit quickly, and Mrs. Givings presses the doctor about whether he is jealous over her hand being on his cheek; he claims that, because of the many shades and degrees of love, the moment was irrelevant and unimportant.
Annie offers to wield the instrument as the treatment has taken longer than usual, and Dr. Givings uses it as an excuse to confront his wife about the slap he heard from the living room.
Catherine begs him to take her with him, explaining how he has seduced her in his talk of beauty and sex, but Mr. Irving confesses he is in love with Elizabeth, who rejected his feelings earlier in the evening when he walked her home.
The curtain falls as Catherine climbs atop her husband and mounts him, discovering the woman on top sex position, allowing her at last sexual satisfaction.
In the Director Presentation Les Waters states the play was inspired by The Technology of Orgasm: Hysteria, the Vibrator, and Women’s Sexual Satisfaction by Rachel P.
[5] The Broadway production, presented by the Lincoln Center Theater, began previews at the Lyceum Theatre on 22 October 2009,[6] officially opened on 19 November and closed on 10 January 2010 after 60 total performances.
[7] The cast included Laura Benanti, Michael Cerveris, Quincy Tyler Bernstine, Maria Dizzia, Thomas Jay Ryan, Wendy Rich Stetson, and Chandler Williams.