I haven’t really seen any oral fake loads other than one or two facials. I typically see fake loads in solos. I think they usually do fake loads not because the guy can’t cum or the sucker doesn’t want cum in his mouth, but because the studio knows “the bigger the better”. That’s why they continually hire big dick actors and use angles to make the actors’ dicks look bigger, because everyone kinda loves big cocks or most people do so it’s a surefire marketing approach to have big dick actors or to make it look like you do.
And this ideology has also extended into cumshots. Most guys only cum 5 mL or less in a load which isn’t a whole lot really, unless the actor has hyperspermia and can shoot like I or others guys do with like 30 mL loads, but that condition is pretty rare and most people don’t even know about it. I think there are a few porn actors who might have the condition but likely just coincidence they are in porn for that alone, like Peter North, Matt Hughes, Preston Parker.
So porn studios and individual content creators have to fake the load to be bigger, since a normal guy is only going to shoot so much of an average cum volume. That’s my thoughts on the main reason why fake loads are used anyway. I don’t really mind if they fake it, but I wish they’d make it look more realistic and stop being lazy with the obvious fake aspects like the cum not shooting from the tip, or the cum consistency being too white or too thick or too watery, or the load being inhumanly big, hell some vids don’t even edit out the squeezing sound of the cum bottle haha.