Question about pedal ornaments in Bach
So I've been learning the organ for a year or 2 and my teacher is pushing me to take the CAGO exam probably next fall or spring (whenever it's offered). I chose Bach prelude and fugue BWV 545 as my first rep option since I like the challenge compared to the other options. I understand the importance of articulated playing and especially in the feet and my teacher has been emphasizing the practice of toe-only playing to achieve that. However, after practicing for a while, I can't seem to find a comfortable way to play the mordents near the end of the prelude with only toes. It seems incredibly awkward and tense to do so and much simpler to use the right heel to assist instead. I'm going to see my teacher again on Friday for a lesson so I'll obviously just discuss it with her, but I thought I'd ask around in advance anyways to see if there's something I'm missing.