Twin Z Pillow Extra Cover

I have two sets of twins. I’ve used the Twins z pillow for my first set, which we used constantly, bottle, feeding, breast-feeding, sleeping in view, and propping them up so they can play toys. My two-year-old twins still lounge on theirs on the sofa. So, I ordered a second one for my other twins. I didn’t realize they had this waterproof cover so I ordered it this time round. My only thing with this cover is that the babies kinda slide off a lot if I’m breast-feeding. I’m gonna put the original cover, over this water proof cover. Together, it works perfectly! Please Twin Z pillow come out with some cotton and linen covers and more color options!