The Ar Tonelico series features a mechanic in which the main character dives into the psyche of his female companions, unlocking powers by travelling deeper into their subconscious. Developer Gust takes advantage of this feature to make incredibly dirty puns.
Last night I picked up a copy of Gust's newly-released Ar Tonelico Qoga: Knell of Ar Ciel for the PlayStation 3, slipped it into my console, and watched the introductory movie five times in a row.
Ar Tonelico III was rated teen in Japan. The ESRB isn't being as kind, slapping on a mature rating on the PlayStation 3 RPG for, among other things, a male character reaching inside a female character's body while she moans.