To urinate on a fan of the opposite team. Taken from the horrific example a few years ago when a group of Oakland Raider fans beat up a Dolphins fan in the bathroom, then proceeded to urinate on him. Typical neanderthal Raider fan behavior.
The Raiders haven't won a meaningful game in years, which results in the fans having to dolphinize opposing fans to gain any satisfaction in life.
The act of removing all body hair, closely resembling the skin of a dolphin. Close attention being paid to the groinal region. Beard, moustache and head hair can be left unshaved (or waxed) and still be considered dolphinized.
Joel came in to work today and said: "Hey everybody, I dolphinized over the weekend. Wanna see?! Now my carpets match the curtains... all hardwood floors!"