I have finally mastered what to do with the second tennis ball. Having small hands, I was becoming terribly self-conscious about keeping it in a can in the car while I served the first one. I noted some women tucked the second ball just inside the elastic leg of their tennis panties. I tried, but found the space already occupied by a leg. Now, I simply drop the second ball down my cleavage, giving me a chest that often stuns my opponent throughout an entire set.