Callicolpia, the rude word that never was

In the Oxford English Dictionary the word "callicolpian" is absent, why is that?
I have never heard the word uttered or see it printed as I just simply joined two Greek words together.
Google tells me that I am not the first to make the word up, but why is it not an OED word, whereas bathycolpian and callipygian are, I do not know.
I must confess the title is a tad misleading as the words are not rude words, just sexual in nature.
The word callicolpian means "pertaning/having nice breasts", bathycolpian means "pertaning/having big breasts" and callipygian means "pertaning/having a nice bottom". The latter is, in my opinion, so much nicer than "bootylicious", but is not used metaphorically (ie. a phone may be bootylicious, but it cannot be callipygian).
I struggle to believe that bathycolpia is callicolpia, but the commonplace of mammary implants makes me think that I may be in minority...