Shurangama Sutra claims that for one to attain perfect enlightenment, one has to complete eliminate all desires - especially sexual desires. Notable examples of our era is Venerable Hsu Yun who attained enlightement.
But the Vajrayanists - especially Tibetan Buddhists - claim that indulging in sexual practices is a must for one to attain enlightenment. There are many examples of Tibetan Yogis who attained enlightenment like this.
Now who is true between them? Who attains the real enlightenment? Also, what is the difference between "enlightenment" and "attaining Nirvana"? It is said in the Mahayana scriptures that one has to spend many eons and lives practicing as a Bodhisattva to attain enlightenment; yet many Chan masters attained enlightenment in one life itself?

