Ok first, when the race time trial begins, go up just a lil bit. And on the ground, on the left side, you kind of see that little patch on the ground. It's kinda big, but yeah. Go up to it, angle yourself to a part of the rock to get up. Now, if you have a game cube controller, press up on the + pad right under the Joystick. Do it about three times. As your doing it threee times, press a muchroom, and hop. Try it about 6-10 times. You'll get it. I tried it my third time, and now I can do the wohle race in 35. 8 secods.
Hope I helped!
I can do this race in around 30 seconds. I use Baby Mario + Nanobike. I get up by going a couple of pixels up to the right, then I do a standing mini-turbo (aiming towards the little clump of mud which raises you towards the rock.). Release, then a milli-second after I release, I use my mushroom. It nearly always works.
I'm working on doing the actualy "circle the " part quicker, I can do it in 30 seconds but I break & slow down a lot.
Edit- Lol, I google searched the glitch... the last post was in '08. =/