What a great idea with the crinkly plastic toy filling! Where did you buy that?? As I will not use that particular block I did not sew it down, but I think a similar stitching like on the lower wings would be fine. Maybe also put some thin batting under the applique of the lower wings to make it a bit puffier.
Look forward to more input, thanks so much.
Ever thought of a ladybug in 3D?
Granny