it's the first option. though let us note that, unlike some moron on the first page was unaware of, hentai only has ONE meaning, and should NOT be confused with "henshin" or "henge", both of which mean transform, only in different contexts. henge (or henkei if you preffer it that way) means the kind of transformation a Transformer does, while henshin is the Kamen Rider style of changing, i.e. metamorphoses into a half-grasshopper monster or using either a magical artifact or super-advanced machine to create a super-suit which usually covers all of your body unless you're a girl, in which case it's very unlikely that it will cover any more than a Japanese school uniform and trendy knee-high boots, and in that case, you're probably going to be in more hentai than any Kamen Rider by the time the second episode airs.