To Comment or Ask Questions about Tumblr, 
Click Here. Please do not abuse the anonymous feature, but if you choose to use it for a question or concern, I understand. Just make sure you are not using it for your 3 blog comments for reading assignments or Dr. French can’t give you credit for your comments.

But not all layouts will show a ‘reply’ option on your posts, so by enabling the ask box you not only allow all people to reply, but you can also answer their questions and replies either privately or publicly. (I suggest you publish classmate comments on your blogs, so they receive credit.) 

To enable your own ‘ask boxes,’ as they are called, look for the Settings option on your tumblelog (the stream for your tumblr posts). There should be an option to allow people to ask questions and to enable anonymous if you choose to do so. If it is not there, then check under the customize feature, under the Advanced tab. 

-Kelli