Sex organ
From wipipedia.org
A sex organ, or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organs according to the strict definition) which are involved in sexual reproduction and constitute the reproductive system in a complex organism; namely:
More generally and popularly, the term sex organ refers to any part of the body involved in erotic pleasure. The larger list would certainly include the anus for either sex, the prepuce, the breasts (especially the nipples) for females, and the nipples for males.
See the wikipedia article sex organ for more information.
