This anime has all of the following: nipples in a Ken Akamatsu adaptation (the only time this has ever happened, so far as I know), a cast led by a very young (pre-Haruhi) Aya Hirano, and an autobot reindeer. All of this in a Christmas special. The world, it be a funny place.
Devilman Lady comes from the highly influential long time mangaka Go Nagai, author of many notable old school manga including Mazinger Z, Cutie Honey, and Devilman. Go Nagai was a bit of a pioneer in ecchi and hentai-hybrid manga, his works almost always contain nudity and/or R-rated adult themes.
Few nude ecchi series are this fun or well made, at least during the season’s first half when it more closely followed the manga. The fanservice was lighter than I would have liked it to be, though any nudity from a company like Artland is a pleasant surprise.
This series probably needs no introduction, but for newer anime and manga fans that are unfamiliar, Tenjou Tenge was the first hit manga by Ito Ogure, writing under the pen name Oh! Great. He would later create Air Gear and a pair of hentai works: Silky Whip and Naked Star.