Shatter may have long since given up foalish stuff but there's one thing that she's always depended on especially when her parents passed, plushies and a blanket that she's had from birth. But most ponies don't know this as she only does this at home, which makes her roommate not take her seriously when she ties the blanket to her neck, wearing it like a cape and holding a plushie.

And it looks like she's cuddling a plushie of her canon self from Bumblebee but a plushie of course.

Anything ABDL related is not at all canon to my story. Shatter in my canon and in general is not an adult foal but canonically she does struggle to self soothe and she does go into a younger state of mind but in a realistic way so she's still an adult, but when she gets in that state, she generally likes to hold her old blanket around and snuggle with plushies, even holding one but most ponies don't know that.