I see that no one seems to explain how someone becomes uncle dad, so I will take the stage. Someone becomes your uncle dad when your dad has sex with his sister (your aunt), producing you in the process. It is that simple. You don't even know if you should call him dad or uncle, so you call him UNCLE DAD.
Girl in school: "That's not funny. His Aunt Mom and Uncle Dad love him very much."
"i will kick my brothers fucking arse son don't you worry"