A Haiduken is a person, usually a male, who has a hairstyle which resembles a person who has just been blasted by one of ryu or ken's Haiduken move (Street Fighter). The hair usually consists of multiple spikes all with enough gel to cut through glass.
"Why are there so many Haidukens at this party???"
An epic sexual maneuver when you restrict ejaculation for some time with your thumb. After enough pressure has built up, you release your thumb and say "hyduken" while spreading your seed. A hyduken can be done alone or with friends.