Here goes my first posting on this forum. I'll try to tie together some Torah thoughts which I heard/read over the years together with my own reflections. Comment/arguments/discussions are welcome.
We're taught that there are 5 levels of our soul, with each level closer to G-d. Weekdays we can access the lower three levels, corresponding to the 3 weekday prayers. Shabbos and Yom Tov we can access the 4th level of our souls, so we also have Musaf. Yom Kippur we access the fifth and highest level (the level of Yechida-unity) so we have Neilah.
The Maharal taught that each of the five restrictions of Yom Kippur correspond to a different level of the soul. And the one that corresponds to the highest level of the soul is marital relations.
This sounds exactly like the theme of Shir Hashirim, where the connection between us and G-d is represented by physical intimacy. We're taught that "all the Shirim are Kodesh (Holy), but Shir Hashirim is Kodesh Hakadoshim (Holy of Holies)". And what was in the actual "Kodesh Hakadoshim" in the Beit Hamikdash ? The Keruvim - male and female. So Shir Hashirim parallels the Kodesh Hakadashim. The Kohein Gadol could only go there once a year, on Yom Kippur. And we're taught the famous Arizal's teaching that Yom Kippur is "Yom Kippurim" - almost as high as Purim. Purim is the day of the year when we're strongly encouraged to use the physical (e.g. wine) to get to a higher state of spiritual consciousness. So male-female intimacy is the bridge between the physical and the spiritual.
The paradox of our battle is that if we always suppress our sexual desires instead of redirecting them, we're killing the very passion which we need to serve G-d. The Gemorah says that when our Sages temporarily killed the desire for immorality, they couldn't find a "baeya" - which literally means an egg - but the Chassidic interpretation was that they couldn't find a "prayer". And in another Gemorah where G-d said "I've created the evil inclination, and I've created Torah as a spice (tavlin)" - a seemingly unusual word because a spice is never the main thing - Chassidus teaches that we should serve G-d mainly with the enthusiasm of the evil inclination. This is the same message we say twice a day in Shma "to serve G-d with all your heart = with both your hearts". Total suppression can work for a while (and maybe it's the only path that works for most of us at the first stages of the battles) but I don't think it's meant to last forever. Maybe this is the difference between Yesod and Malchut, between Yosef Hatzadik and Dovid Hamelech.
Sometimes there's a category of acting out which is associated with the highest spiritual feelings. Someone can be feeling an intense yearning for a connection and it feels like the only way to connect is to do something forbidden. When a person is in this emotional state, the word lust isn't an accurate desciption at all. A feeling of Dveykus (rapture?) is probably a more accurate description.
Here's an idea I've been thinking about. It seems intuitive to me (but I haven't seen it anywhere) that the ten tehillim of the Tikkun Haklali parallel ten different emotional states which can lead to sin. Each one of these tehillim is teaching the tikkun for that particular state, and when we recognize ourselves overcome by any of these emotions, we can redirect our emotions instead of acting out. For example Tehillim # 42 - "like a hart yearns for springs of water" - corresponds to the feeling of Dveykus I mentioned above, which could be redirected to thirsting towards G-d and doing something intense which you never would have done otherwise. Here's my tentative list of possible emotions corresponding to these Tehillim. I'm sure I'm wrong for some of them, so if you like my general theory then please let me know if you have any other ideas:
Tehillim # 16 - optimism vs. pessimism
Tehillim # 32 - depression because of sins
Tehillim # 41 - deprivation, sickness
Tehillim # 42 - dveykus (see above)
Tehillim # 59 - fear, loneliness ?
Tehillim # 77 - personal misfortune, sadness
Tehillim # 90 - ? feeling of years wasted ?
Tehillim # 105 - self-esteem
Tehillim # 137 - mourning
Tehillim # 150 - pure joy/ecstasy