Cat lick trigger

Question
Whenever my wife or I scratch our cat on its lower back, it triggers hime to want to lick something, whether it's our hand or his fur.  We were just curious about why this funny thing happens.  Is this true in other cats?

Answer
Mark,

Yes, this is, indeed, true in other cats.  This stimulus can also trigger other responses in other cats, e.g. scratching itself with the back leg as if there is an itch, putting the bum way up in the air, putting the bum way down on the ground, etc.

I wish I had an explanation for this, but I do not.  So, just enjoy this little behavioral quirk.  

Best regards... Norm.