Just when you thought they had finally hit the limit with the straightforward titles in the novels.
They get more straightforward the longer they are, generally. What amazes me is how "ecchi" novels have become more and more overtly porn without actually getting titled "hentai". I always find it really stupid/frustrating, too, since there's some sort of "blueballs" at work that makes ecchi stuff absolutely obsessed with breast groping 24/7 without actual penetrative sex, but hentai stuff can generally have a better plot both in and out of the sex scenes because of it.