Sexual act with the female on top. The female does a split and inserts lubed penis into vagina. The male then grabs hold of the female's legs and spins her around rapidly, similar to that of a helicopter's blades.Has a high failure rate, roughly 100%. Failure results in Female either falling over or vomiting, and Male losing penis. Theoretically , a successful helicopter, if done fast enough, could generate lift for the female for about 2 seconds. There have been 3 reported cases of success, but they were all in Japan so you never know.