When a man sees a beautiful woman it is natural for him to feel energy in his body, which he usually interprets as sexual desire.
Rather than dispersing this energy in mental fantasy, a man should learn to circulate his heightened energy. He should breathe fully, circulating the energy fully throughout his body.
He should treat his heightened energy as a gift which could heal and rejuvenate his body, and, through his service, heal the world.
Through these means, his desire is converted into fullness of heart. His lust is converted into service.
His desire is not converted by denying sexual attraction, but by enjoying it fully, circulating it through his body (without allowing it to stagnate as mental fantasy), and returning it to the world, from his heart.