No clue about the IPAD, but depending on the browser it's usually a right click that gives the option for incognito, private, or whatever name that browser uses.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .