A multi-participant sexual experience which includes at least one cousin

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 an anal gang bang, when an anus is full of several loads of semen, the owner of said anus inserts a variety of ingredients such as vegetables, meat, etc. and then clenches the anus shut to trap all of the sperm loads and food. This causes the food and semen to "cook" inside of the rectum.