The perfected ancient art of doing something really homosexual or odd, or something along the lines of jizzing in a public place. The art reaches its peak, in the part where after doing said act, you yell a random, confusing phrase at your company, and make a daring escape. The facts prove that moses led the israelites out of egypt by pulling a horny manfish. History's great escapes have all been, in reality, real examples of horny manfishes.
Please note that the word has nothing to do with the definition.
Holy shit he just pulled a great Horny Manfish!
Ha! After cumming on the table I have yelled GENGHIS KHAN and therefore pulled a horny manfish!