manilla_ex, for penis,vagina, etc. You can call them all 'asoko' meaning "over there" or translated properly to "down there".
Penis: Chimpo/Chinko (either way is fine, and with the second, be cautious when saying you want to play Pachinko.
Breasts: Oppai or Mune (I can't do the italicised e here, but yo uget the idea)
Vagina: A very dirty way is manko. Don't say it around women or they'll beat your ass for being vile.