first go to chrome wed store and type in "TumTaster" then click "add to chrome"
(FYI it's an extension)
Step 2: Search
now that your ready go to google (or other) and type the song name and/or artist then add tumblr to it. then click on which ever
(ex "I love it" by Icona Pop)
Step 3: Download
the audio player will have a black box under it so now you right click the "click to download" button and click "save link as..."
Step 4: Music player
you can also click on the box and it take you to to a black page with a music player in the middle, you can check the url to see if it a nice file or mystery file (will have a mess up name ex "atemdcfvsoinvcbasdih") the url should be short and have .mp3 at the end
you just right click the the triangle (ie the play button) and click "save video as..."
Step 5: Tips
if using google chrome wait til it download (at the bottom box) and then click on it so it open in your iTunes
by any chance the song info is only the name play it and right click on the box and click "find in iTunes" and then put all the information in (Get Info)