The term that is yelled whilst physically or verbally sexually abusing a friend.
It was originally an acronym for Random Acts Of Sexual Abuse, but grew out of control.

The word raosa, when said negates the gayness of any activity, for example: A guy slaps another guys ass, and says "RAOSA!"

That would be NOT gay.

A guy slaps Josh's ass and walks away.

FAG.

Also makes sexually abusing girls okay, but isn't recommended unless the girl has a sense of humor.
A really good sense of humor.

Finally, When RAOSAing a new person, you must tell them what RAOSA is before leaving.

When you eat dirt for the first time and leave your family to build a shack in the woods