Billie Baby Milk Bath Soak Tub - Onefloor.com.au. $16.95. Are you looking at a red, irritated baby bottom? A baby with heat rash or nappy rash? The Billie Baby Bath Soak is an ideal product to help soothe and moisturise sensitive, irritated skin. The combination of Australian goat's milk (known for its soothing, skin loving properties) is combined with colloidal oatmeal to produce a soak that is an ideal choice for nappy rash, heat rash or irritated skin.