One can never control the sexual instinct — which has its roots deep within the psychophysical personality — through physical means alone. The majority of the troubles produced by the sex idea originate more at the mental than at the physical level. Unless something inside us responds to outer stimuli there cannot be any physical reaction. Therefore, the problem lies inside us more than in anything we generally call the ‘object of temptation’. Hatred towards the opposite sex or fleeing away from the world is not the means for rising above the sexual instinct. Hatred is nothing but negative attraction. It is subjective change that is required.
Many a time we give to certain images stored in our memory a
disproportionate sense of reality. As a consequence, their attraction acquires
such strength that our conscious mind becomes confused. At that stage, we do
not even want to think of the unreality of those images. We forget that images
are only images; they become in us real persons, real situations, as it were,
leaving us thoroughly bewildered. We should learn to deflate these images and
deprive them of life. It is difficult, no doubt, but this is the way to obliterate
them. Incidentally, before attaining some dexterity in the process of
sublimation, concentration of the mind may negatively influence our sexual
imagination. Concentration of the mind, if not properly directed, makes even
harmless pictures dangerously vivid and living, harmless emotions very
passionate.
The tactic to be adopted in these cases is never to allow
the mind to form disturbing pictures and brood over them. This is achieved by
producing counter-thoughts. When there is attraction towards a particular
person, for instance, the mind could be instructed to regard that person as a
mere shadow, as someone unsubstantial. Then, the charm and influence produced
by that person diminishes and the situation becomes more manageable.
Source - excerpts from article titled 'Brahmacharya and Its Practice' by Swami Yukteshananda published in the Prabuddha Bharata Magazine January 2010 issue.