The equivalent of roofin or beachin but on a cruise. You go on
top of your cruise ship at
night and since there are no lights and you are on the middle of the ocean you can see the entire
universe without any light pollution. You chill up there with your friends, contemplating life, the universe, humanity, and chillin with the nice cool sea
breeze blowing across the ship. This is considered the purest and ultimate form of the roofin, beachin practice/art since there is no light pollution although roofin and beachin can still be performed in areas where there is no light pollution on land. Another term for Cruifin is Cruise Toppin.