Well, I think the "Secret Mark" scene was probably Jesus doing a ritual to create a High Priest. I'll paste the link to a site that talks about that.

But biblical ritualism seems to have sexual origins. John Allegro thought that the High Priest was "dressed as a penis, anointed with various saps and resins as representing the divine semen…"

I do think the 'secret' scene was meant to be somehow understood as a sex scene.

https://rogerviklund.wordpress.com/2014/05/04/an-occult-priestly-installation-ritual-in-the-secret-gospel-of-mark/