when somebody puts their peanut butter on the bottom of the sandwich and their jelly on top, they're a bottom. if they put the peanut butter on top they're a top.

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.

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The male who receives the anal penetration in gay sex and, usually, but not always, performs the oral.

A person who is on the receiving end of gay sex. It is often confused, and assumed that the bottom is submissive, however a bottom can be dominant. (See power bottom)

someone who is on the bottom in sexual intercourse or harry styles

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