A 4-5th c. Coptic manuscript now in the British Library (Ms. BL. Addit. 5114), acquired under unknown circumstances by a Dr Askew, contains a gnostic text which bears the title of the Pistis Sophia. Another copy was found in a 5th century codex unearthed at Akhmim in 1896 also containing three other texts (now P.Berol. 8502). The text of the Pistis Sophia was translated from the first copy by G.R.S Mead in the late 19th century.
In the Pistis Sophia, chapter 147, on p.381, l.6-20 of Schwartz’s edition (Copenhagen, 1925) appears a condemnation of a Borborite practice recorded by Epiphanius. It appears in a list of sins and penances to be endured in the afterlife. Here is Mead’s translation.
Thomas said: “We have heard that there are some on the earth who take the male seed and the female monthly blood, and make it into a lentil porridge and eat it, |387. saying: ‘We have faith in Esau and Jacob.’ Is this then seemly or not?”
Jesus was wroth with the world in that hour [p. 322][ and said unto Thomas: “Amēn, I say: This sin is more heinous than all sins and iniquities. Such men will straightway be taken into the outer darkness and not be cast back anew into the sphere, but they shall perish, be destroyed in the outer darkness in a region where there is neither pity nor light, but howling and grinding of teeth. And all the souls which shall be brought into the outer darkness, will not be cast back anew, but will be destroyed and dissolved.”
Or as Tardieu puts it:
For the sacrilegious gnostic … there is neither instruction nor judgement; he is sent directly into the exterior darkness to be destroyed.
The ascetic gnostic does not care much for the libertine gnostic, it seems.
UPDATE (6/12/13): I have corrected some misunderstandings about the contents of the manuscript and added more detail, and a note about the Berlin copy.