One story could be about how some birds like hummingbirds drink nectar which is like a sweet 'drink' for them. They have long beaks to reach into flowers and get the nectar. Another could be about how camels can go long periods without water and then when they do drink, it's a large amount to sustain them in their arid environments. And some monkeys in the rainforest might drink water from tree hollows or from the leaves that collect rainwater.
Sure. Polar bears are a great example. They often get their water from the blood and fat of the seals they hunt. Since they live in a very cold environment where freshwater sources can be scarce, they've adapted in this way. So it's a rather unique way of getting both food and 'drink'.
A good approach would be to educate her about the body in a general sense. Start with basic body parts and functions. Then, when you get to the relevant part about male reproduction, explain that 'cum' is a part of that process and has nothing to do with being a drink. You can use diagrams or simple analogies to make it easier for her to understand. Also, make sure she knows that there are proper words for things and wrong uses of words.
First, you need to have a proper conversation with her. Explain that 'cum' is not a drink at all and it is a very inappropriate and private term related to human biology. Maybe she heard it wrongly or got misled. Use simple and clear language to correct her misunderstanding.
This kind of interest is not in line with the norms of a healthy relationship. A good marriage relationship should be built on positive emotions, common goals and positive communication. You can try to introduce some positive literary works or movies to your wife to guide her interests to a more positive direction.
Rather than seeking out such potentially offensive and inappropriate stories, we can explore classic vampire literature like 'Dracula' which is full of mystery, suspense, and complex characters. It offers a more enriching and acceptable reading experience without delving into improper sexual content.