To start with, I have 4 musicians. That's ok for playing some famous Mozart melodies. But if I want to play a Beethoven symphony, I will have to upgrade. But if they don't have any instruments to play, they just stand around. It's just the same as with testosterone.
Sexual intercourse is a concert.
The musicians are the testosterone, and the musical instruments are the receptor sites. All is set and running at the concert hall. They play Mozart melodies. However, such an experiment is no proof that liberally sending more musicians onto the stage will make for a full orchestra, capable of presenting that Beethoven symphony. I have to supply the additional violins, drums, and trumpets as well.