Awwwwgasm is a precious gift of evolution, designed to reward us for the act of reproduction, so that we will desire to perpetuate our species. It is a mechanism which seems to work very well!
We higher order mammals have discovered that we can achieve the same intense euphoria by self-stimulation, and so we do.
There is that joke that goes: Why do dogs lick their balls? Because they can.
And, as Woody Allen said: Don't knock m4sterbayshon; it's sex with somebody you love.