This is (IMHO) a bad UI approach on your side anyway. If these tooltips are valuable, why are they visible (prominently displayed) only on the first visit? And

This is (IMHO) a bad UI approach on your side anyway. If these tooltips are valuable, why are they visible (prominently displayed) only on the first visit? And if they are not valuable (most of the sites overvalue their content - visitors stats should help you assess that) you should just get rid of them anyway. I am not saying cookies don't have their place, but being misused as they are I like keeping my cookie jar clean too.