Megumi Kiyosato: Wet Your Heart (1986)

Megu, a Sperm Planet from far away space. There is a legend on the Sperm Planet that if you have sex with a virgin Earthling, you will gain eternal life. However, this is limited to sex with a man you love. Megu approaches a man she meets. What is love? Megu's crotch glows and she suddenly bites him. "If Sperm Planet doesn't drink semen regularly, it becomes painful..."