How to display an add content form inside another content view page? Basically I'm looking to make a beefed-up comment system. I'd like to have a content-type B that acts as a comment like entity for content-type A.

Question: When content A is viewed, at the bottom of the page the node/add/content_type_B form should be there with a 'Save' button which will create a new piece of content. Is it possible to render the content type B add form inside the content A view page (no Panels/Display Suite please)?
With Advanced Form Block you can use a "Node add" form has a block, you could show it at the end of your node content using regions or node tpl file