Saw some people asking so thought I'd make this post to help people Multi-Quote like a Ninja Master.
Replying to multiple Posts:
First part is easy. Just hit the +Quote icon on any post of any page as long as it's part of the same thread and it will get added to the queue. If you change your mind about adding that post, just press the -Quote icon instead. Simple right? When you are ready to reply, head down to the bottom of the page and you will see a grey box saying "Insert Quotes...". You can also press the "More Options..." button and the "Insert Quotes...' button will be there also.
When you press the "Insert Quotes..." button a dialog box will appear and you can either remove quotes you don't want or rearrange the order of the quotes. When ready just close the dialog box to continue...
Replying to a single large post:
Here is where the fun happens. Highlight the section of the post you want to reply to and it will turn red, from here you can either add it to the Multi-Quote queue by pressing +Quote or press reply to respond to that part of the post directly. From here you can keep highlighting different parts of the post and add it to the Multi-Quote queue that we learned about above or alternatively you can highlight then press reply next to the highlighted text to keep adding different parts of the post manually into the dialog box at the bottom.
Hope this was helpful for all you Ninja Quote Warriors!