Marijuana has been used as an aphrodisiac for thousands of years. The ancient Indian Ayurvedic medicine systems used cannabis to increase libido, produce long-lasting erections, delay ejaculation, facilitate lubrication, and loosen inhibitions.

Some Tantric sex practitioners drink a substance called bhang, a sort of spiced marijuana milkshake to enhance the sexual experience. According to one source, Indian prostitutes eat bhang sherbet to help them feel sexually aroused.

 In 19th-century Serbia, female virgins were given mixtures of lamb’s fat and cannabis on their wedding night to make sex less painful. Morocco, Egypt, Lebanon, and other Middle Eastern and Northern African cultures used cannabis for sexual purposes in a potent form known at kif as recently as the early 20th century.

So what exactly is it about weed that turns people on?

Besides the obvious — it heightens your senses, relaxes you, and makes you feel hyper-connected — there are also physiological effects. Along with an increased heart rate, changes in blood flow and respiration, William Novak, author of the 1980 tome High Culture: Marijuana in the Lives of Americans, says, “Neurochemistry, hormonal systems, and brain regions such as the temporal lobe are affected by both marijuana and sexual arousal.”

That’s because THC (delta-9-Tetra-hydrocannabinol), the active ingredient in pot, not only releases dopamine in the brain — thereby causing the “high” — it also replicates the effects of a sexy little naturally occurring neurochemical called anandamide.

But pot doesn’t always make sex better. For some people, it has the exact opposite effect. Which is helpful if you’re a monk. Ascetics and monks have used marijuana to free themselves of sexual desire. Instead of connecting them to their bodies’ sexual desires, or other people, it helps them meditate. In the context of a sexual encounter, it can be tough to focus on making your partner come when your mind is busy contemplating the meaning of life. Or if being high makes you suddenly hyperaware of everything wrong with your relationship.

The effects of smoking also depend on the person’s tolerance for the drug — a couple of tokes may get one person in the mood while another user may need to get really high in order to feel that heightened sexual awareness.

Of course, when it comes to pot, you can have too much of a good thing. Heavy, long-term marijuana use can result in low motivation — including the motivation to have sex. And whereas some folks report an increased libido — in one study, men said they achieved bigger, harder erections and women said they became wetter and were more able to achieve orgasm when stoned — others may report an inability to sustain an erection.

It is commonly believed that smoking marijuana causes reproductive system damage, and has a deleterious effect on the production of testosterone and other hormones — which in turn can affect fertility, menstruation, and erectile dysfunction, among other things. Pot prohibitionists like to haul out the “pot will lower your sperm count” argument, though studies on this subject have produced conflicting results.

It is true that the cells of the reproductive system are very high in fat, and thus absorb and hold more THC than most other cells in the body, a factor that has led some researchers to believe pot can lower testosterone levels. Apparently, in some cases, male pot smokers have developed man boobs because of localized fatty deposits.

Still, according to Novak, “There have been no epidemiological studies which have shown increased infertility in marijuana-using humans, and studies of overall reproductive rates have found no reduction in reproductive rates in countries where a higher rate of marijuana use is found.”

And the National Organization for the Reform of Marijuana Laws (NORML) cites study upon study indicating that reported lower sperm levels return to normal once marijuana consumption ceases.

So put that in your pipe and smoke it.