Ukemi = bottom: the verb ukeru means to "take, receive, accept," thus uke (receiving) mi (body, party) means "one who receives," or, "a bottom." Neko = bottom: neko literally means "cat". It has exactly the same meaning as ukemi, but in a slangier way.
I found this on tumblr a while back, and finally decided to share it with all you lovely folks. I present: Professor Willow by Reapersun
Since the implementation of The Criminal Code in 1907, Article 175 forbids distributing "indecent" materials, it is believed that most pornography in Japan must be at least partially censored. The primary means is to put a digital mosaic over genitalia.