silent communication; knowing each other's thoughts without speaking, feeling the same even when being apart.
casual conversations and perhaps slightly inane, but never feeling the pull of time.
being in love.
having the same moral precepts without preaching it to each other, albeit feeling a slight joy and surprise when you find out about your mutual agreements.
when your expectations match.
when love doesn't get in the way.
hand-jobs (it's like a lost art)
when selfishness doesn't get in the way.
when you have each other's backs.
when loved ones stand up for you.
holding hands in public.
when you understand why you've argued and what to say to mend things back and make them stronger.
open-mindedness.
empathy.
when you understand each other's fears, the fear of loss, the fear of not gaining, and comforting each to either discard the loss, or not sweat the gains.
when you're secure enough in your relationship not to feel the slightest hint of jealousy.
laughing really loud.
when someone cooks for me.
knowing when to walk out of a fruitless endeavor - and having the courage to do so.
dancing a semi-sexy semi-silly dance to a song with a pretty girl
perhaps:
http://www.youtube.com/watch?v=aaao6z4FN5sdemon sex in the back of a Corvette while Finnish death-metal blasts from the speakers.