Editors (WQ); Linda E. Savage (Huffington Post)

Sex is not the way to the Brahma (higher) worlds in the Fine-material Realm (
rūpa-loka) beyond the Sensuous Sphere (
kama-loka).*
Brahmacariya (literally, the vehicle, means, or career to those lofty worlds) means abandoning sensuality (
kama). But, believe it or not, most people are neither aiming at rebirth in the Fine-material Brahma worlds nor the higher worlds of the Formless Realm. They are content to live in the Sensuous Sphere. This sphere includes numerous "heavens" -- semi-terrestrial and lower-celestial worlds -- as conceived of in Greek rather than Judeo-Christian culture. The Five Cords of Sensuality are:
pleasurable sights
pleasurable sounds
pleasurable savorings
pleasurable scents
pleasurable sensations

The height of pleasure for beings in the Sensuous Realm, where beings enjoy these Five Cords, seems to be the practice of sex (
methuna-dhamma, DN 27.16). It engrosses us. And sex is able to stay within the
Five Precepts.
If our spiritual ambitions are modest, and no one is being harmed, sex should not simply be practiced. It should be enjoyed and expressed free of misguided guilt and shame. (Otherwise, it leads to abuse, hypocrisy, and perversity). Sex may even be spiritualized, that is, taken beyond the physical. The Huffington Post's Linda E. Savage explains how:
How to Make your Sex Life Spiritual(Feb. 26, 2008) People blame philosopher Rene Descartes for the modern idea that spirit and body are two separate and antagonistic entities. I don't.
Spiritual Sex: Begin the Practice(Aug. 10, 2009) When we rouse sexual energy, it is like a sleeping serpent come to life:
Kundalini. Sexuality is much more than a physical act.

For those who prefer to stick with the guilt and shame model (recovering Catholics, Jews, and Fundamentalists of every stripe), here are three specially selected stories:
*Buddhist Cosmology
Brahma-world: in the widest sense, a name for the Fine-material world of Form (rūpa-loka) and the immaterial or Formless world (arūpa-loka) beyond it; in a narrower sense, however, it is a designation only for the first three heavens of the Fine-material world. Cf. Brahma-kāyika-deva.
Brahma-kāyika-deva: The "heavenly beings of the Brahma-world" inhabit the first three heavens of the Fine-material world (rūpa-loka), corresponding to the First Absorption (jhāna). The highest ruler of them is called Great Brahma (Mahā-Brahmā). Cynically he is said (DN 11.81) to pretend: "I am Brahma, the Great Brahmā, the Most High, the Invincible One, the Omniscient One, the Ruler, the Lord, the Creator, the Maker, the Perfect One, the Preserver, the Controller, the Father of all that was and will be." Cf. deva (II. 1-3).
Graphic as seen on a Sri Lankan Buddhist monk's blog (prevaids.org)