man forced to compete in contest where if you win you are killed and you body is used for reproductive material

Short story from at least 25 years ago. A man visiting a planet is forced to compete for the right to die and be used for reproductive material or die trying. The men on this planet intentionally put themselves into deadly situations, so they can use their strength and reflexes to save themselves. If they die, then they weren't good enough. The men, including the visitor have to complete an extremely difficult and dangerous obstacle course. At the end of the obstacle course there was a giant woman, like over 30 feet high. And the reason the woman doesn't kill him is because he stops to talk to her instead of just going between her legs to be crushed for genetic material like the local men who manage to complete the course do. She says she will tell everyone that he completed the course and became part of the planet's gene pool. She helps him escape. The story was making an analogy: the men were like sperm competing to fertilize the woman's egg.