Adding follow buttons to MENU on all pages

I want to add a Twitter follow button preferably above the NAV links in the menu to appear on all pages, and I have no idea how to do this. I tried adding a text box to the sidebar and posting code in there and saving it, but nothing appears so I’m assuming that the menu where the nav links are is completely different than the sidebar and that I don’t have a sidebar on the site. Is there a simple way of adding the code to the menu so that it will appear on all pages under or above the nav links?