Automatically put a menu on every post

Without knowing where exactly you want to put this (all posts, certain categories, etc.) I will give you the way to do it across the board.

First step is to go into functions.php and find the function where your menus are being defined. Inside that function add the following code:

register_nav_menu( 'dmca', __( 'DMCA', 'theme-slug' ) );

NOTE: Replace theme-slug with whatever the textdomain is in your style.css file.

This will add a new menu named “DMCA” that you can then fill with whatever options you want.

Then, in your single.php file, add the following code in the location where you want the menu to appear:

wp_nav_menu( 
   array(
      'theme_location' => 'dmca',
   )
 );

This will place the menu you defined earlier in this location. I suggest looking at the developer resource WordPress has for wp_nav_menu() as it has many more options you can put in that array such as adding classes, id, etc. to it as well.