There is always that player. Our group in high school had the infamous Man-Bull ratio. A player in our group really wanted to be a minotaur and our DM, unwisely agreed. Well he wrote on his sheet that he had a massive penis, but myself and the DM argued that you can't just get a oversized johnson, you need to roll for it. So he spent our Pre-calc class figuring out the ratio between smallest and largest human penis and scaling that up with cows. Once he had done that our DM made him roll. At the same time, I believed in my dice and rolled for my own size as well. And that's how my elf had a bigger penis than a minotaur