hmm.. depends how his mood is when he bite your jeans..
if he is like very sad.. mean he dun wan u to go out..
like my dog.. whenever i go out.. he look very sad and he dun wan to look at me..
but if he is in curious/ playful mood.. mean he may want u to bring him out or play with him.
but if ur dog is not trained.. it may be just a bad habit that he is bite ur jeans when u go out.