Physical reaction to a disturbing thought or image. The thought itself makes one physically pucker their ass muscles due to the actual thought.

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.

When someone sticks their finger down the crack of their butt and then swipes it across someones nose. Same technique as a wet willy. Pronounced But-twilly.

The act of placing one's finger into another anus for the playful enjoyment of one or multiple individuals. The finger may be licked prior to insertion similar to the Wet Willy procedure. However, due to the decreased accessibility of the anus the wetting of the finger is not imperative.