Penis-in-Vagina Sex Introduction: There are many concerns that people who have penis-in-vagina (or, sex-toy-in-vagina) intercourse face. These include pleasure, discomfort, positions, the size of the genitals, and more. People wonder about the hymen, the thin layer of tissue that partially covers the opening to the vagina, and that can break during first intercourse. Others are curious about strengthening the muscles that are involved in intercourse, in the bodily fluids that accompany intercourse, and much more. This extensive channel discusses these and others issues pertaining to this type of intercourse.