I preffer natural remedies for a child it's safer, so I will suggest you give her papaya (pawpaw) fruit salad this a natural laxative.
leave papaya to be very soft to be able to scoop with a spoon, and pour milk over as dessert the whole family can eat too. Try it, it's very effective.
All the best
One thing that I am going to say is that she should probably be tested for chrons, colitis, IBS and even cilac disease. All of those can cause some degree of difficulty with BMs.
If I were you I would look into these few diseases.
I can understand your concern ..enema's are stressful so are suppositories, as I said start taking a blase attitude about it, I do know that even in younger children once they form a fear and an anxiety its hard to get through to them, they switch off.You have to get this cycle restarted .it may require more miralex but try not to put a lot of emphasis and focus on the issue ,she is seeing your concern and it is making the matter worse . It sounds as if she was potty trained early,so an emphasis on going to the potty has been ingrained in her head from an early age ..lessen the emphasis ..dont be worried about whats happening to her body she is picking up your anxiety ..
yes she is potty trained and we have tried Miralax actually for 6 months- on miralax she would go about every 3-4 days but I didnt feel comfortable keeping her on something like that for so long. We have also tried suppositories and even enema- neither of which really work for her and we didnt want to stress her out more with those. It seems with her every time we try something new it may work for awhile then she gets used to it and goes back to holding. I'm mostly concerned with what the holding is doing to her body.
I have noticed a pattern of behavior in children , the more you make an issue about something the more it becomes so I do suggest less talk about it, let her poop on her own .She may need some Miralax ,a clean out.as 6 days is a lot. ask the Doctor about this .She is only 2 year old is she potty trained ?