I think the correct way of doing this is to use django sessions. Basically each user (anonymousUser included) has a session during its stay on the website (or even more).
If you have a form that you want to store for a specific session, you can do it by using
request.session['myform'] = form
you get it by
request.session['myform']
and you can delete it using
del request.session['myform']
Basically Django pickles a dictionary of the session and saves it in a place (typically the database, but can be on other place as explained in django sessions).