Crunk skis with tips on both ends, and usually dope graphics as well. They are used to get sweet air off of jumps and out of the stunt ditch, or to grind rails.
Not to be confused sith skiblades, skiboards, or snowlerblades. Those are all quite flaming.
Dude: Woah. That dude is skiing the wrong way!
Other dude: Nah dude. He's on twintips.
Skies with tips in front and in the back. So you can go forward and backward. Neat.
Look at me! AUCH F**K! DANM!