Inflatable baby bathtubs?

I also has this prob with my son .. we got the duck tub and it worked pretty well but he could still move his bottom around...but not as much. The biggest prob I had with it was he liked to lean on the sides and front so I was more worried he was gonna fall out the side. { he never did I would never leave him even for a second while he is in the tub} I only used it for about 3 months then he was in the big tub. If you can't find a tub with a "no slip" bottom maybe you can make your own with a small tub mat or the little tub decals that are used in the shower? Just not sure how well that would be on her lil bottom. I hope you find something that works