[header] How to block someone on tumblr [title] Log into your tumblr account to access your dashboard. [step] You can block a tumblr user from being able to interact with you right from the dashboard. To open the dashboard, log in to your tumblr account on the web or in your mobile app. 
[title] Click (or tap) the avatar of the person you want to block. [step] This will expand that user's blog on the right side of your dashboard.