Water Balloon

My older sister taught me this technique, its great. When I was 14 my sister Meaghan caught me jilling and decided to teach me how to really get off. Our favorite way is to use a balloon (one of the long skinny ones). Put several marbles inside the balloon then get a squeeze bottle with some warm water in it. Fill the balloon part way with the water but be sure to leave air in it too so it will slosh around. Then you can walk around or go dancing and it will make you cum over and over. I have one in now and came twice typing this.