Creating an image on a surface with the help of an intermediate and (aerosol) ink. The intermediate dictates where the ink will reach the surface. Both the intermediate as well as the print are called stencil.
Source: https://en.wikipedia.org/wiki/Stencil (derived 15-7-2016)
I like to use the skin as a stencil. It gives a very direct image. In visual arts this technique is called: pochoir. This technique was used in cave paintings dating to 10,000 BC, where human hands were used in painting hand print outlines among paintings of animals and other objects. The artist sprayed pigment around his hand by using a hollow bone, blown by mouth to direct a stream of pigment.