Let’s get this out of the way: vibrators, vibrators, vibrators. Vibrators! Now let the giggling subside. Hysteria is a new romantic comedy, directed by Tanya Wexler and starring Hugh Dancy and Maggie Gyllenhaal, about the unlikely invention of vibrators in 1880s London. This presents a problem in discussing the film, since every word about it—touching, cheesy, lush—seems filthy and funny.

“Everything takes on a double entendre when you’re talking about vibrators,” says Dancy, who plays Mortimer Granville, the charming doctor who invented the thing. “We spent the first few days on set giggling over everything. Then, by mutual assent, we decided to grow up.” Dancy, by the way, pronounces “vibrators” as “vi-BRA-tors.” Endlessly hilarious.

To be fair, Hysteria isn’t only about vibrators. It’s about the Victorian milieu and its gross economic disparities between classes, its friction between an almost medieval understanding of medicine and Dr. Lister’s germ theory, the invention of electricity, and the nascent women’s rights movement. Also, Granville falls in love with Charlotte Dalrymple (Gyllenhaal), the free-spirited daughter of his employer. Dalrymple works in a poor house, rides a bike, and bucks social mores. Whilst he falls in love, Dr. Granville is also frigging a large percentage of London’s wealthy spinsters. (Sidenote: This is also probably your only chance to see Hogwarts matron Madam Pomfrey [Gemma Jones] achieve climax on film.)

“Above everything else,” says director Tanya Wexler, “this is a romantic comedy.” So while themes of class, gender, and politics are gently stroked, they’re never more than rubbed. Hysteria builds a gentle warmth, achieves peaceful climax and, of course, a happy ending.