From Cracked.com’s 5 Weird but Effective Alternate Uses for Sex Products

#1. Write a Secret Letter in Semen

It’s 1944, and this time you’re a British spy. God, you are so cool. This really makes up for the time your mom found your dildo collection, right? Anyway, spy stuff: You need to get a message to your contact, but you know it will be intercepted by the enemy. They can detect invisible ink. What do you do? What would Jason Bourne do? What would James Bond do? And then you have your answer: You start furiously masturbating.

Wait, What?

It’s true — one of the British’s secret spy weapons was whackin’ it.

Semen, it turns out, is a very effective invisible ink. Like other invisible inks, semen is undetectable when it dries out, but it has one big advantage over its competitors — it doesn’t react to iodine vapor. Since iodine vapor was the main detection method for invisible ink during the war, writing code in semen meant that even if a message was intercepted, its secrets most likely wouldn’t be revealed. For a male spy, at least, it was plentiful, easy to transport, and always available. Female spies probably preferred to take their chances with the iodine.

This technique was actually used in the field, where only one flaw was found — its distinctive smell. While fresh “ink” apparently didn’t give off too malodorous a scent, one spy in Copenhagen stored his jam in jars, causing his letters to “stink to high heaven,” and was told that a “fresh operation” was necessary for each communique. “Fresh operation” is easily our favorite World War II slang for jerking off, beating out “doing my bit for the war effort” and “loosing the soldiers on the beaches of Normandy.”

Oh, and the guy whose research lead to the discovery of semen as invisible ink? His name was Cumming. History: It’s the gift that keeps on giving.