But what to choose? There’s rhino horn (ecologically unsound), blood from poisonous snakes (no, thanks), oysters (bit pricey) or mandrake root (not from my local grocer) or any of about 500 so-called aphrodisiacs. For centuries hopes of sexual conquest have been pinned on these bizarre substances. None has ever been proved to work and at least one has been a terrible blunder.

I’m talking about Cantharis vesicatoria, otherwise known as Spanish fly. This little emerald-green beetle is killed and crushed and sold on the basis that it drives women wild and makes men better lovers. And people buy it.

The Spanish fly is a blister beetle - and blistering is what it does best. It contains cantharidin, a natural compound long used as an irritant or direutic. It is also highly toxic - 20 beetles’ worth or 1mg has been known to kill. Smaller doses cause serious stomach problems and irritate the uretha, increasing blood flow to the region - hence its reputation as an aphrodisiac.

A French doctor reported that legionnaires suffered priapism - “erections douloureuses et prolongues” - after eating the legs of frogs that had eaten Spanish fly. They felt sick, not sexy. Around the same time in Victorian England there were cases of manslaughter and poisoning as a result of Spanish fly, but still it sold.

Research in 1996 by the US Federal Drugs Agency showed that cantharidin has no sexual effect, but the porn industry continues to flog it. Which brings us back to the Marquis de Sade. In 1772, France’s notorious sexual adventurer employed four prostitutes for a good time with himself and his manservant. De Sade offered the women sweets containing cantharidin.

Unfortunately for him, the women became ill and he ended up on trial for poisoning. Doctors could now tell him that cantharidin is nasty, but not useless. Forget romance and think wart removal.