Masturbation at the bar

Today at 5.30 pm I left the museum where I am following an exhibition and pass a bar in the historic center.
The restaurant has a few small tables outside with backless stools.
I observe the customers outside and my eye falls on a couple.
He of middle age, with a few short-sleeved graying hair, she, a beautiful brunette dressed in darker looking younger.
They are tourists.
I notice that through the leggings he is masturbating her.
You can really see the fingers inside her pussy.
I can not believe my eyes.
As I have seen, who knows how many will have seen the scene.
I turn around and see that she is enjoying.
I keep watching from afar, then I return, but they have gone away.