The shape formed when you have a threesome consisting of two guys and one girl. With the girl on her hands and knees with a guy at each end. One man is getting his penis sucked while the other penetrates from behind. While these acts are taking place the two men are high fiving each other because they can't believe that the chick agreed to this act. With every thrust the 'A' tends to wobble.
Chad and I took that 18 year old up to a room and gave her the wobbly A.