Reminds me of me and my first love... on a grassy area with plenty of people around... just heavy kissing, that's all... but we were so wrapped into each other that we really were far far away from everyone else... and I think that this creates a bubble of energy, a kind of shield, which makes this distance more real, keeps others at a distance. Same here, but you noticed it because part of you resonates with that.
But what I don't understand is the young man's facial expression. And the body positions are very awkward... so it doesn't really seem all that sexual, or intimate, despite the posture. It makes me a little confused by what is really going on.
Still, very interesting... them and the people nearby, unaware...