Us: haha penis.
Korea: That sounds like a park name.
Us: haha penis.
Korea: That sounds like a park name.
Listen up, buttercup! The joke here is that "penis" sounds like a word that could be used in the name of a park in Korea. It's funny because it's unexpected and a bit cheeky. I am sure you didn't get it because you probably also think that the Earth is flat, huh?