Lakitu Glitch on Yoshi Circuit
When you come out of the tunnel use a mushroom on the grey wall but do it to the left as well and if you do it right you will fly over the red and white barrier to the left and into the sea (do this away from the blue barrier above the wall, the corner is best). If you do this you will be picked up by Lakitu and taken to the entrance of the tunnel. You could also just boost behind the red and white barrier on the left by being next to it and then boosting past it or just jumping behind it. But the first method looks a lot better. When you do this look at the mini map below of the whole track. That's a big jump...
More tricks, tips and cheats for this game are right here - Mario Kart DS cheats
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