1 definition by the guy next door.

The men's faithful companion. Testosteron or C19H28O2, as known by nerds and such, is the good friend you make in school, you meet him in 9th grade and you get along with him well. Highschool he is in your class so hes always with you and more than 75% of the times you do something "wrong" he has definetely something to do with it, the boy's best friend, from then on he's a friend for life and it will constantly be with you until he dies (andropause).
You can blaim him everytime a girl calls you pervert but the fault will always end up being yours.
Basically he drives the car but oficially you crash it.
Great summer day on mall you can't resist and grab that juicy ass, "You pervert!", "Geez sorry its the testosterone". *SLAP*
by the guy next door. January 22, 2009
Get the testosterone mug.