Thanks Ilian.
I watched with little time at disposition the documentary (not all) on you tube, and I didn't find the sequences of the prey offering.
But I've seen the sequences of the female building her nest for the eggs: and this fact let me think about another intelligente snake species, the king cobra!
About prey offering, I do not consider impossible this fact, on the contrary. But the observation of one or only two of those types of behaviour could be also casual and not purposely intended by the male...
Just as it could happen that I lose my wallet on a street and someone picks it up...
Nasal "markings".
I do not think it's intended for protecting (?) the scales from transpiration.
In Greece I've witnessed this behaviour, and those were temperate spring days (not hot days!) during courtship season.
And: what can do against water loss (which is anyhow utmost low with thick scales!) a very subtle layer of nasal secretion?
Captivity is something else, sure.
But in the terrarium it seemed to me that during some periods the nasal glands were more "swollen" and the snakes had more urge to mark not only their belly scales, but also, and with regular zig zag designs, the walls of the terrarium. Against the evaporation of the terrarium walls in this case?