Love the lyrics Phill. Though I must admit when I saw the title I thought about Billy Connelly talking about his willy  and  the Scottish lady telling him its not size of your Willy that matters  is how you use it.   Putting my stupid mind aside I think what happens when some men  grow up they do change after they settle down with a lady, People's goals and interest  change and so on.  Sometimes that means they don't have as much in common with their old friends as they use to. Your song has described that  perfectly even though it  is a made up event it would resonate with many. When I was a Kid I had a group of  mates and we called ourselves the Musketeers the old " One for all, . All for one" .
I went to a school reunion years later after not seeing these guys for years apart from childhood up until about age twelve, we had very little in common.

Shwmae Pete? ( your name in Welsh would be Pedr)

I never thought of the Billy Connelly connection but I must admit it began with the first line leading to a song full of double entondres but I couldn't keep it up, pun intended. I then thought, as you did of my old school mates and meeting up 50 years later all we had in common was friends that had died! The last verse was a statement of fact, as we get older we do tend to meet girls or boys, and we drift away from them and only meet up or correspond occasionally!
So I guess it's funny yet sad