Internal injection is definitely more hot and sexy but what does sex have to do with eating cum? Why the hell do they swallow pussied or assed cum? Is it really sexy for some out there?
I think it is because is almost like the physical embodiment of lust, and when you see someone actually consuming it, it kinda blows your mind! I never used to like it, but with the guy I am with now, I love it. I guess it just depends on the person.
Creampie is in the pussy, not in the mouth. You've got your terminology wrong. As for the question, if you gotta ask, you'll never know.