The action of performing anal sex in order to preserve ones vaginal purity. Most extreme religious couples practice this before marriage, although in almost all religious publications this is looked up as a worse offense.
In the case of homosexual relations, this is the only way for a men to perform intercourse with each other.
"Have you heard that Tom and Bill have a dry-erase board in their bed room?"
"No, whats it for?"
"I have heard that is used to keep score of who has had the most orgasms
while they are saddlebacking each other. I also heard that they participate in the convergence
practice after they finish."