I use Canesten (or the generic brand) on DD's bottom with my MCN's without a liner. You can tell it's water soluble as it washes straight off your hands and rubs in clear. Nappy rash is technically a fungal infection even if it isn't thrush so it's a handy cream to have. I wouldn't use yogurt - yogurt is good for vthrush because it's just the discharge, but if the infection is in the skin you need to treat it with a proper anti-fungal. HTH.