@1DOLLAR
ecchi is kind of a subgenre, its basically a step back from hentai but too explicit to not be atleast labelled. From wikipedia 'used when it has sexual content, such as not much clothing or nudity, but does not show s**. '.
You'd be surprised. Highlighting size differences and making proportions ridiculous is pretty common, and it's also just an artistic choice to really highlight how they see eachother too! Italk is like, 4'11, and hyunwoo is like 6'2, they do kinda have a big difference.