Having someone complete the act of masturbation by pulling up and down on the forearm, while the male holds his own penis. This can be done with an infinite number of males. If and when someone ejaculates, it must be done onto a single Nutter Butter. The last person to orgasm must eat this cookie, thus becoming a Brudder for life.
Fraternity initiates; Sam, Dave, Diego, Bill, Steve, and Rod all pair off and begin the Dutch Rudder Nutter Butter Brudder challenge, Bill lost and now must eat the Nutter Butter. Bill is definitely a Brudder.
When you and another man have had sex with the same women.
Man 1: Ya I totally hit that last night. Man 2: Dude, I just creamed in her last Saturday, we are Nutter Brudders.