See below quote from Bart Erhman's book...

Heretical Gnostic Gospels? or Christian lies? If this kind of a gospel existed, where is it and what happened to it? 
What is the basis for this story? Were there some religious voyers or was this a part of a dogma? If this Christian 
lied about reading this, why would he lie and what else would Christians lie about or suppress knowledge about
to assemble the canon and the dogma? 

Should be an interesting conversation at a Bible study  to demonstrate to Christians that there were many 
heretical gnositc gospels that never made it into the cannon (Gospel of Judas, e.g) A regular Christian's brain would 
explode and from my experience they cannot talk about in rational terms about Gospel of Mary, Gospel of Thomas, 
Gospel of Truth, Gospel of Philip, Gospel of Judas.

Bart Ehrman has a video where he talks about this particular gnostic cult in which followers of Jesus actualy even would eat menstrual blood of women they are having sex with, plus practice ritual masturation and sex outside of marriae.

Bart Ehrman

"Jesus Interrupted" page 117

Diotemus forged and then circulated fifty obscene letters in the 
name of his philosophical nemesis Epicurus. This obviously did not 
do wonders for Epicurus's reputation. I have sometimes wondered 
if something of the sort is happening in one of the more peculiar 
forgeries of early Christianity. The fourth-century heresy hunter 
Epiphanius indicated that he had read a book allegedly used by a 
group of highly immoral Christian heretics known as the Phibion- 
ites. This book, The Greater Questions of Mary, allegedly contained a 
bizarre account of Jesus and Mary Magdalene, in which Jesus takes 
Mary up to a high mountain and in her presence pulls a woman out 
of his side (much as God made Eve from the rib of Adam) and begins 
having sexual intercourse with her. When he comes to climax, 
however, he pulls out of her, collects his semen in his hand, and eats 
it, telling Mary, "Thus must we do, to live." Mary, understandably 
enough, faints on the spot (Epiphanius, The Panarion, book 26). This 
strange tale is found nowhere outside of Epiphanius, who is famous 
for making up a lot of his "information" about heretics. I've often 
wondered whether he made this whole account up, claimed to have 
found it in one of the Phibionites' books, but fabricated it himself 
out of whole cloth. If so, in a sense he forged a Phibionite book in the 
name of Mary in order to make his heretical opponents look very 
bad indeed.