If he's only just old enough to go out then maybe you are rushing him...its a big world! Try putting the lead on him indoors and following him around, put the lead on before meals and let him eat with it on...do tiny walks around the garden. Most breeds don't need on lead walks till about 6 months or older. an you carry him out in your arms or take him for car rides before you try on lead walks again. Please don't leave a trailing lead on him indoors, always hold one end or take it off, I know of a lady whose cav puppy broke its back when a trailing lead got entangled in a chair