How do men increase their sex drive?

Men achieve arousal, or physical penile erections, as the result of actual stimulation (seeing, hearing, or otherwise) or from remembered or imagined stimuli. The most effective arousal is by touch, followed by sight or sound.

Pubescent (teen) males can achieve arousal at inappropriate times due to hormonal changes, and many discover erections upon waking, despite having no conscious memory of sexual dreams or thoughts.