A Lament - Very Impotent

Years ago, when I was young
I thought myself as, oh, well hung,
Until one splendid August's day
I went with Bob to good old Kay.

There I learnt I'm average, just,
But size is not what counts in lust.
I still enjoyed my jive and bounce;
Life was full of ups and downs.

Now I grow old and older still,
The won't gets stronger than the will.
As I await the final thaw,
My member follows Newton's Law.