Definitions by Josh Osborn

Braincest 

In certain circumstances, two children will be born, sometimes even from different parents, and they will be siamese. However, not siamese physically, but mentally. If such children with siamese brains partake in any physical activities, it is called braincest.

Kathy and Jake are getting married? That's braincest!

Braincest by Josh Osborn May 23, 2008