I assume this is for the first TSC, (ie. to escape the forest). As much as I would like to say that there is a guaranteed method to execute this trick, sadly that is not the case. If you were to look at previous WR runs you would even notice that there are times when even veteran runners fail this trick first time.
However, practice makes (nearly) perfect. I shall describe the method I use:
After chopping down the sign next to the exit, I line up against the wall and do a 180 degree turn (then pressing L). The camera should appear over Link's head, facing down. If you were to imagine the analogue stick as being the face of a clock, I tap the analogue stick in between the 8 o'clock and 9 o'clock position, as it is not a 90 degree turn I aim for. Then I TSC and hopefully clip past the guard.
Again, even this fails for me sometimes, but I persist. There are plenty of videos that show off this trick, but if I have enough time I can upload one with commentary.