When you have to go poop so bad that it keeps coming partially out and you suck it back in to avoid messing your pants. This usually happens on a long trip, or when you can't get to a bathroom, or when it would be socially inappropriate to take a dump.

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 you have to take a crap so bad that it feels as though the turd is moving in and out.

When one's feces repeatedly breaks the anus plane, touching air, and returning from whence it came. This is generally due to inconsiderate parents insisting, "We'll be leaving in five minutes" throughout the course of a two-hour trip to Lowes.

When you have to drop a load so bad, the head of the turd keeps poking out of your ass then slipping back in. Similar to how a prairie dog pops up and down in their hole, appearing and disappearing.

A phenomenon where, in a landscape of office cubicles, a number of people stand up to look around over the tops of the cube walls. Usually an unexpected/loud noise or verbal exchange will cause the curious to rise like prairie dogs out of their holes. The people will scan the cube horizon and soon sit back down.

When your feces starts bobbing itself in and out of your anus because you have to take a big shit but can't find a bathroom and can barely hold it in. Similar to a prairie dog popping in and out of the ground