How do I detect collision point between 2 balls?

so, I have 2 balls...

They are both instances of the same sprite, which is a physics object. I want to spawn a one shot particle when they collide. Obviously I want this to be at the point of the collision. They are rotating, which probably makes it harder.

Is there an easy way to just detect the x,y co-ordinate between the 2, bearing in mind they are the same sprite?

wow, that is the kinda response I was hoping for! That's perfect- thanks very much