My little boy loves sleeping on a pillow (very thin) but I put it under his sheet so he can’t move it about or over his face, he doesn’t sleep with blanket or covers as he hates them but I’m also terrified to introduce them in case he puts it over his face 🙈
Normally after 1, with my older 2 introduced when around 18 months
I think it's not recommended until they are 1 x