This troper practically elevated this into an art form when writing an essay for his philosophy class. The assignment was to analyze the "people-seed" metaphor in regards to abortion. It asks the hypothetical question that if babies were born through seeds that drifted through the air like pollen and grew by latching onto carpets and upholstry, and you opened a window to air out a muggy room, would it be morally permissible to remove an unwanted baby-plant from your house? As part of my essay, I pointed out that there were other ways to air out a muggy room, such as an air conditioner or a ceiling fan. This greatly amused my professor, who thought I was using those alternatives as metaphors for masturbation or oral sex. I wasn't, of course, but I got an A on the essay anyway, so who cares?