The best I could do was 214D~C(release)->6DD->236A->214D~C(hit)->2DD->D spam. Granted, I tried it on the PSP version and my trash execution is made worse and it is hard to set up the optimal conditions for this(namely getting the dummy to double jump at the right time).
I also got 214D~C(release)->6D(CH)->236A->214D~C(hit)->dash 2DD->jC->j2C->2DD->D spam.