When the girl you love is telling you how much she really loves you and it gives you a boner. Often leads to the best emotionally charged lovemaking.
Girl: Baby you really are the love of my life.
Girl: Are you hard?!
Guy: Sorry, it's an emotional boner.
noun- that feeling that you get when you are head over heels over someone. Or whenever you are emotionally charged usually involving a significant other.
I have so much chemistry with this boy and he knows where to touch me. He gives me an emotional boner.