The Brothers Grimm told the story of a princess who kissed a frog, who turned into a prince, and, in the versions today, lived happily ever after.

Incentive to kiss amphibians has never been more dubious than a fairy tale, but science shows that there may be something to making out with one-specifically, a toad.

Well, not necessarily kiss. Toad venom is the main ingredient of a Chinese aphrodisiac called Chan Su. Applied to the penis, it causes a numbing sensation that will take you on a wild ride.

However, like any concoction dealing with toxins, Chan Su has to be properly prepared. Good luck getting it in The States though-the main ingredient, Bufotenin, is classified as a Schedule I substance. Well, there’s always Cialis.

Regardless, that princess and prince must have had one hell of a night! Know more.