The act of propping open a woman's anus with a metal ring and placing one's testicles in her. Remove the ring and the testicles will be trapped inside her until the women releases her sphincter and passes stool. The act of the woman shitting one's testicles out is called "fifth base".
My girlfriend wanted a little more than anal sex last night so i decided to take her to fifth base. The ring hurt her but not as much as her ass hurt me!