Quite recently I was "Browsing" the various and many posts on our vast forum on SoM, and came across Personified's Magick and Sexuality post, I have included a link below:
She Mainly covers the Norse views of it, I took the personal liberty to write a post on the Hermetic views on it.
It is often seen as Aleister Crowley/Frater Perduabero to be slightly vulgar, gross and out of place when he Masterburated to be closer to god, in a sense he was right. hermeticists believe that the Fires of Sexuality and Love, give energy to our Solar Body, our Solar Body is the thing alchemists call the philosophers stone.
The Solar Body is an interesting thing, it is one of the Four Subtle bodies believed in by hermeticist alchemists, and is greatly looked upon as conscious immortality, it corresponds with Gold.
Masturburating, Sex etc. Increases the power of the inferno within your Solar Body, thus fueling it.