This one’s interesting, but it doesn’t tell or imply whetere these people are related in any way. Ore am I missing something?

Intended ambiguity – read into it whichever relationship is the most disturbing for the reader. Older brother, younger sister, or maybe father daughter, or uncle niece. Wanted to contrast the overpowering immediate sexual drive of the male with the more thoughtful further reaching (in this case positive) consequence for the female, and how they are both satisfied in this taboo act.