how do you differentiate between bukkake and gokkun?

i read something that was like "most Americans think they know what bukkake is, but most of the time they're just watching gokkun, which is bukkake lite!"

i mean, i've seen bukkake, SO I THINK, and i am interested what differentiates the two and whether i am, indeed, being a stupid American. i'm hazarding a guess that bukkake is multiple men and gokkun is one or two, because i could definitely envision some American seeing a guy jerk off on a girl's face and be like "BUKKAKE!! HAW HAW HAW!!"
 
why does it really matter? does it come up in your regular conversation often enough that you need to make the distinction? or is alex just boning up for teaching in southie?
 
google explanation:
Gokkun: gokkun is eating sperm since it sounds like the gulping girls make. You will often hear girls say gokkun in Japanese movies. It is a term used to describe the sound of girls swallowing semen. Thus, we hear the term "Gokkun Girls" a lot.