IUD's are not advised as a primary birth control when the male partner(s) are well hung. The hugeness of the penis, pounding into the cervix, often dislodges the device, making it ineffective. So, if a woman's intentions are to have sex with well-hung men, the IUD should be low on the selective method of birth control. I believe most doctors would say the same. Plus, based upon the type of IUD, many women have bodily rejection of the copper-based units.
