The mystery is finally solved !! We often see Cristiano Ronaldo doing goal celebration with a hand gesture, and we wonder what it means exactly. We can only assume that he was meant to honor his son with doing that, and that's correct.
On his Twitter account, one of a fan actually had the brain to asked him about his hand celebration meaning. And as simple as that, Cris answered the question
"Honoring my son".- @abbeymayor hey Ronaldo, what does that sign u do with ur hand when u score mean?
So, the simple question is answered...:p