Breast jiggle, becomes deformed and stops moving

Hi all,

I made for fun a model with breast physics…
I used a mirrored box which go over breast
I followed a video on YouTube…

Anyways it appears when I do a fast movement the breasts fold inside the chest and the box which aninates the breasts stop moving

Any ideas to stop this happening?

when softbodies fold, try to increase the pull and push power of the springs in softbody edges.

edit: better increase the bending value