P.S.
M., I have been a childcare provider for many years. One of
the things I have learned is SOME kids think that part of them
is going down the toilet and they are afraid. You might try
putting her poop down the toilet and let her flush. (Try and
make it a fun thing) Since she likes to be in control, SHE will probably want to do it herself which gives you the opportunity to tell her when she goes poopoo, she will be putting it in the toilet all by herself. She will see she
is still all there and she doesn't feel different.
Good luck!