Build difficulty: Medium
1. You will need 4 balloons, some duct tape, 1 latex glove and a cheap vacuum flask (aka thermos or Dewer flask). Dismantle the flask so that you are just left with the outer casing (you don’t need the inner vacuum part). Any larger body will do. A Pringles tube will be too small.
2. Put all four balloons into the large end of the casing. Lay them on the edge.
4. Carefully blow some air into each balloon. Do this one at a time – putting in just enough air so that the balloon inflates to the midway point in the body. Once inflated – seal and attach the balloon in place with a bit of tape on the outside of the tube.
5. Carefully fold the glove cuff over the end of the body casing and hold in place with tape or rubber bands.
6. Lube up well and enjoy!