Floyd Mayweather's Bodyguard: Best Xmas Gift Ever? ... Floyd Once Gave Me ...

What do you get for a Christmas gift when your boss is the highest paid athlete in the world?

That's what we asked Floyd Mayweather's bodyguard Big Church at LAX Tuesday ... and his answer didn't disappoint.

Big Church -- part of the "The Great Wall" security squad that protects Floyd -- says every day is like Xmas with Floyd (since they travel all over the world together) ... but there's one gift that stands out.

BTW, this year alone ... Big Church has been to Rome, Dubai, Moscow, Milan, Saint-Tropez, Monaco, Turkey, London, L.A., NYC, Vegas, Miami, Havana and more.

... and all while traveling in private jets.