There was a variety of teachings and practices among the second-century gnostics. But they all seemed to agree that Yahweh (the demiurge) is a lesser god who is so arrogant that he thinks he is the supreme God. He was the creator of all things material and soulish. The supreme God is the Father of Christ who is pure spirit, and who leads the gnostic to deny material things and escape the imprisonment of the body, and become pure spirit himself. One group of gnostics believed that they should so entirely deny the flesh, that they should remain virgins and never engage in “filthy koinonia.” Another group of gnostics believed that since the flesh is the creation of the demiurge, it is useless, and the gnostic must eventually escape it and his spirit go to heaven. So since the flesh is worthless, it doesn’t matter what you do with it. For that reason, this group of gnostics engaged in promiscuous intercourse.
It may be that some of the second-century gnostics believed in annihilation of the uninitiated. In the gnostic “Gospel of Philip,” it is written in section 90, “Those who say they will die first and rise again are in error. If they do not first receive the resurrection while they live, when they die they will receive nothing.” This may mean that after death they will not live again.