The act of closing ones eyes as tightly as possible while swirling around their "junk" ferociously immitating a helicopter. The trick is finding the surprise afterwards.
Lance Maynard is a lonely man that has to resort to a blind helicopter every night so he doesn't kill himself.
For a guy, while masturbating, at the point of climax, he closes his eyes and gyrates his dick around in a circle, getting jizz everywhere, but is unable to see where it landed until he is finished and opens his eyes.
Lance had to clean his sheets after pulling a blind helicopter; jizz was everywhere!