Tsubaki, a wife, at the behest of her husband (who is infertile but longs for a child), ends up having sex with a man she finds on the internet who calls himself a "sperm donor". This man is more physically fit and better educated than her husband, but Tsubaki's attitude is hard, always telling him, "I'm just trying to get pregnant," and "Don't touch me, don't even kiss me." However, the man's masculinity is far superior to that of her frail husband. He has a huge penis, amazing stamina and great skill...