If this aspect sits in your natal chart, the odds are you've never thought of yourself as a 'difficult person'. From the inside it looks like this: will and feeling don't argue. When you decide to do something, your emotions are broadly on board. When you want quiet or rest, your reason doesn't read it as weakness. You rarely catch yourself in the sharp split between 'I must' and 'I want' that people with squares or oppositions between the lights live with. To many this doesn't even seem remarkable — it seems like the way everyone is built. It isn't.
Sun sextile Moon is a neatly assembled inner arrangement in which the conscious personality and the emotional nature are on friendly terms. You can explain to yourself why you want exactly this job, exactly this person, exactly this kind of life. Feeling doesn't pull against your decisions, and your decisions don't ignore your feelings. In your relationship with yourself that yields a calm the people around you often read as maturity or an inner backbone.
Now comes the central subtlety, the one that makes the sextile worth reading about on its own. This aspect works only on request. It doesn't push you in the back, it sends no pain signal, it engineers no situations where you urgently have to grow. It simply lays two well-tuned instruments side by side and walks off. If you don't pick them up, nothing happens. That is the shadow side of the soft aspects: you can live a whole life without once putting them to work. Outwardly everything is fine, but the real measure of who you might have been stays off-screen.
In my consulting room this turns up again and again. Someone arrives with a sextile of the lights in their chart and says, 'Everything's all right with me, I just want to understand which way to move.' There genuinely is no inner conflict. But there's no movement either, and no request as such — because nothing hurts. And it's pain, more than anything, that shifts people off the spot. When there's no built-in tension, the impulse to develop has to be manufactured by you, and that is a separate skill.
What helps? Setting tasks on purpose. Any concrete goal — from finishing a degree to learning a language inside a year — makes the Sun and Moon work in tandem. The will sets the direction, the emotions supply a steady fuel, with no burnout and no sabotage. Without a task they simply lie next to each other and the aspect seems 'unexpressed'. In fact it is expressed in an ordinary day, as softness, flexibility and quick recovery. But the potential of this pair runs well past everyday comfort.
There's one more thing worth naming: your relationship with your parents and your past. Sun sextile Moon often means you aren't at war with your own childhood self. The image of the mother and the image of the father aren't torn apart inside. That's no guarantee the family was ideal, but in the child's perception the roles didn't badly contradict each other, and the grown person doesn't burn energy endlessly reprocessing childhood stories. The energy that for others drains into trauma work stays free in you for other things. What you do with it is a separate question.
In short, this aspect is a free resource that nobody activates on your behalf. The inner compatibility is there, it's real, it looks after you. But turning it into a fully lived life is your own work. The sign the lights occupy, the houses they fall in, and their links to other planets all shade how it plays out — to see exactly how the pair is wired in your chart, and which concrete tasks would draw it out most, you'd want a full natal reading.