There are four processes in the practice of brahmacarya (celibacy). First control the sex impulse and sex vasana (habit) through dama (control of senses) and pratyahara (withdrawal of the senses), then practise conservation of sex energy. Shut all holes through which energy leaks; then divert the conserved energy into the proper spiritual channels through japa (repetition of God's name), kirtan (chanting), selfless service, pranayama (yoga breathing) and study, vigilance, self-analysis, introspection and vicara (enquiry). Then have conversion or sublimation of the sex-energy. Let it be converted into ojas (spiritual energy) or brahma-tejas (Brahmic radiance) through constant meditation (brahmacintana) and Lord's grace.
A vedantin diverts his mind through asserting, "I am all-purity. I am sexless atman (self). Om. Om. Om." A bhakta (devotee) diverts his mind through japa, kirtan, service of guru (preceptor), service in temple, study of Bhagavatam, Ramayana, etc. A karma (active) yogi diverts his mind. He is ever occupied in some kind of useful service or other. A hatha yogi converts the sex-energy through kriya yoga and dharana (concentration) and pratipaksa bhavana (meditation on the opposite) method.
In common parlance brahmacarya is single life. In yogic parlance it is restraint of, not only sex-indriya (sense), but all senses. All senses contribute their own share to sexual excitement, sexual urge. The sight raises impure thoughts. Food strengthens the sex indriya, as tongue and genitals are born from the same source. Hearing of love, talks, touch, smell - all excite passion. Therefore all senses must be controlled. Repression or suppression of sex-energy will not help much in the practice of brahmacarya. What is wanted is sublimation. Sex-energy must be entirely converted into ojas sakti or spiritual force. In transformation the gross form assumes a subtle form. The gross semen becomes a subtle force; this is also not enough. Sublimation only gives full protection.
Lustful gazing at women, talking on love matters and about women, gluttony, too much sleep, shaking of body and aimless wandering, a desire to be in the company of women, are all forms of lust. Abandon all these. Practise purity in thought, word and deed and get established in satcidananda svarupa (essential nature as existence consciousness - bliss absolute).