To have doggy sex with a woman and have people in yor closet with cameras jump out. Your partner will then attempt to get away. The point of riding the bull is to see how long you can keep your dick in her. But beware, she may make an awkward turn and could bend your dick.

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 are pounding a chick in the ass, reach around and grab onto her titties and yell "I HAVE AIDS", then try and stay on as long as you can.

When doing a chick up the ass, you say or do something to make her freakout and want to stop. The goal is to stay on and in as long as you can.

See bucking bronco.

When doing a chick from behind, lean down to her ear and whisper the name of a different girl that you've had sex with implying that you think it's her name. See how long you can stay in as she tries to get away.

to "ride the bull" - during vaginal, doggy style intercourse, to withdraw the penis and shove it directly and forcefully balls deep into the anus of your unsuspecting parter. and of course holding on until she throws you off or you get off. Works the best with anal virgins.

You bring a fattie home from the bar and while you are having doggystyle sex with her, you whisper, "you are the fattest, most disgusting thing I have ever seen." Then you try and hold on long enough to blow your load.