Baby stops her poop.

Jed

My 16 month-old daughter is still learning how to coordinate bowel movement straining and opening her anus. She strains but immediately closes stopping the poop. She is not constipated as her stools are mushy normal. Is there a way we can force the poop out just to relieve her? How do we exercise this bowel movement coordination? How do we lessen her pooping phobia? Thanks in advanced.