My dd 2yr4months has been amazing doing wees in the potty but she wont poo on it! I keep encouraging her but shes just not wanting to do that part. She asked for a nappy so I gave her one and she didn't poo but I noticed she'd done a wee. I took it off again and out knickers back on as I don't want to set her back on wees now from having nappy on for 5 mins! Any suggestions?