chemistry behind checking out females
First of all, I understand young men that you are all young, and therefore horny as hell, and therefore insist that all men are polygamous by nature... but what's the chemistry, the thought, the desire behind checking out other (than your girlfriend's) skirts?
Now I don't need replies such as "well, it's just a reflex" "it's a guy thing" "I can't control it" and stuff. I want an honest, observant, and immaculately precise answer: what exactly happens in your brain when you see a female walking down the street and what are your immediate thoughts, physical and mental reactions? (Am not a hater, just curious)