Trimix requires next to zero outside stimulation. Applied directly to the base of the penis ( Take a look at the Trimix Instructional Video ), results will generally occur within 10 minutes. Depending on the patient’s requested strength a trimix injection can last anywhere from 20 minutes to 2 plus hours. Trimix is a mixture of three compounded medications; Alprostadil, Papaverine, Phentolamine. For those that have had minimal success or experienced uncomfortable side effects with oral ED meds it is a highly effective alternative. Unlike oral ED meds, it is safe for patients on nitrates and alpha blockers.
The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.