My daughter lays on her back with her feet in the air and squeezes something.

Jessica

So my daughter has been doing this since she was around one years old. she lays on her back with her feet crossed up in the air and squeezes either a blanket or a stuffed animal and when she’s squeezing it she starts shaking. I already mentioned it to her doctor but her doctor has no idea why she does it . Anyone child do this ??