If you've added an AdSense for search box to your page, you're probably aware of the relevant search results it provides your users. That being said, a few publishers have asked us if it’s a violation of our program policies to perform searches in their own AdSense for search boxes. The short answer is no, this activity is not explicitly prohibited by our program policies. http://adsense.blogspot.com/2008/09/is-it-right-to-search-on-your-own-site.html
Do not use the search box on your site associated with IP address. Flags and horns will be raised by the algo.
Don't click on the sponsored links on the top of search results. Even searching boosts your impressions, so i try to avoid searching on my sites.