Neil Patrick Harris has been discussing his nude scene in David Fincher.s Gone Girl and he.s revealed that he has a unique method for preparing his manhood before he steps in front of the camera in his birthday suit: the windmill. Neil Patrick Harris made the revelation during his appearance on Conan O.Brien.s talk show, Conan, explaining that he developed his technique alongside his How I Met Your Mother co-star, Josh Radnor, whom with he starred on the hugely popular sitcom for 9 years. According to Harris, the pair worked together in a play in Los Angeles titled, The Paris Letter, where they played lovers, and one scene saw them both walk out in the nude. To get ready for the scene, Harris admitted that before they went on stage they used to perform the "windmill" and the "helicopter" with their penises to get them into shape.