My son is 3 soon as is potty trained but Hates using big toilets in public, luckily he's managed to hold it in till we got home but we walk everywhere and whenever he says he needs to wee I show him the different toilets and he immediately changes his mind and says he doesn't anymore.

I can't be walking around with his potty it's impractical but I was told about a portable potty and wondered if that would help?

What would you suggest... A portable potty or the toilet seats for big toilets?