Most accurate way to sex is to vent but aside from that a good way to guess is by looking at the blue lines under the eyes and the iridescence of the scales. Males tend to have stronger lines in their beard and their scales tend to be a lot more iridescent, where as females lines are more broken and they are less iridescent. Even males can have what looks like a egg tube, penis, during breeding in my experience. As for the aggression that's pretty normal for a male to display and the nuchal hump is mostly down to genetics. Hope this helps.