I made a level to show the effect: Spider Mario's Maze (but I didn't share level with you guys,too embarrassing)the timing of the move is tricky, and takes practice, but it is doable, and gives you a new way to secret things in your levels. In that level, I provide the catch point with combos of 36 Cave Wall Slope and 42 Cave Wall Slope on the left and 38 Cave Wall Slope and 44 Cave Wall Slope on the right. Those are steep enough that Mario will naturally fall if he hits them, but if you hold a direction, and hit the border between those tiles, you can catch the tiniest of discrepancies in the hit detection at the border between tiles, providing your "landing" spot.
Glitch work? Takes practice!
