Name that Move! Can you?

Ok im not taking credit for this move, but i can find the name of it. I was sitting on a lover's dick the other day, which was about 7 inches. I took it all the way in and pushed out, causing my rectum to go down and the sigmoid to go around his dick. I kept pulsing till he came, and asked what i was doing. I told him and we both giggled, cause i was essentially jerking him off with my intestine. Does anyone know what this sex act is called?