Pleasure Center Circuitry
a random thought on sexuality
You have an enormous amount of nerve endings in your genitals and nipples. These nerves lead directly to the pleasure center of the human brain.
During sexual intimacy, you move certain parts of your body against certain parts of your partner's body. (That's not all you do, of course, but bear with me...) Your big, complicated brain is sending motor signals to your muscles, telling them when to move.
Thus, your motor signals translate into sensory signals in your partner - your movements are stimulating your partner's erogenous zone(s). At the same time, your partner's movements are stimulating your erogenous zone(s). A feedback loop is formed: the two pleasure centers talking to each other through nerves, muscles, skin, and erogenous zones.
So, one point of view on sex is that it is simply a conversation between two lumps of neurons, simulatiing each other to orgasm.