When two men stand in front of each other, face to face, with their two erect penises almost touching. Their Jap's eyes are alligned so they are staring directly at each other. Once in the right position the men start masturbating their own penis until one of them ejaculates. The first one to ejaculate into the other ones Jap's eye wins the contest.
Luke: How about a Japanese staring contest Zak?
Zak: I would like that very much Luke!