Here's a scan from an old book by George W. Carey (esoteric Christianity author). This segment talks about the importance of conserving sexual energy in order to enhance the function of the pineal gland.
Unwin looked carefully at dozens of cultures with an eye to whether or not they regulated sexual relations between the genders...and then drew the conclusion that strict monogamy led to more energetic societies (measured in terms of their accomplishments...according to his perception).
He wasn't looking at "continence" in the sense that J. H. Noyes uses it in Male Continence. However, as conventional sex leads to habituation, the net effect probably *was* greater continence.
The Secret History of Western Sexual Mysticism: Sacred Practices and Spiritual Marriage by Michigan State University professor Arthur Versluis (2008) is a refreshing look at sacred sex in the West. Versluis bravely pulls a lot of sacred sex traditions out of the pigeonholes into which academics have placed them, and re-examines them. The book is short, which makes it an easy read, but it is not comprehensive.
Miscellaneous, and in some cases rather extreme, quotations about ejaculation
Dalai Lama, b. 1935
We have within ourselves a certain potential which we can explore further. And among these four states, the best opportunity for further development is during the sexual intercourse.
The divine Sophia [female aspect of God, another name for "Wisdom"] have I loved and sought from my youth,
I have desired her to be my spouse.
Ever have I loved her beauteous and radiant form.
Ever have I prayed that she might be sent to abide with me,
that she might work with me to the end
that I might know what I lacked
and what in me God would find acceptable.
And since she had ever known and understood,
had guided me in all my life's activity,