When two women shove ice cubes up an anus and a cherry bomb right after that. The receiver must be ready to shit otherwise the experiment wouldn't work, then as the cherry bomb lights, there will be a cold and shit covered explosion within the anus which can form a sense of pleasure for some people. This will may be illegal in some countries as it can be seen as an attempt of rape.

When you eat dirt for the first time and leave your family to build a shack in the woods