When jizz dries on one's dick tip from beating off the night before. When they wake up the next morning and try to piss, it comes out in two directions like a viper and showers the walls and floors.

The safeguarding of Earth and other worlds from biological cross-contamination (i.e. billionaires with too much time on their hands).

Also known as “planetary protection.” Planetary protection / quarantine “reflects both the unknown nature of the space environment and the desire of the scientific community to preserve the pristine nature of celestial bodies until they can be studied in detail.”

There are two types of interplanetary contamination. Forward contamination is the transfer of viable organisms from Earth to another celestial body. Back contamination is the transfer of extraterrestrial organisms, if such exist, back to the Earth's biosphere.

After sex, cum dries in the end of a man's schlong. When he tries to pee, it comes out in two streams like a viper's tongue. It usually happens after a night of drinking.