The air of intensity when you're together will push you to express yourselves in a deep and focused way. You'll find, however, that you have an easier time putting your impressions and emotions into words than your friend does. You might even discover, after you've been facing down your issues and ferreting out your deepest, most buried emotions, that they've been using you as an emotional projection screen.
You could even start to feel like little more than a mouthpiece for their emotions, the ones they're unwilling to express because the feelings are too weird, intense or otherwise unacceptable. If this happens between you, the effect could push you even further into the negative possibilities of this aspect's influence: You could start obsessing over their problems. Be careful that this influence doesn't wear you out.