Like dinner at the Olive Garden, Hippos are disgusting. When the male hippo is pretty sure one of the ladies in his neck of the woods is ready to get down to business, he seduces her in a way that even the majority of Cracked staff have never engaged in, at least not more than once.
Like a sly poon hunter out at the bars, the hippo positions himself where his potential mate can see him. Then he shits himself. To be fair, he also pisses at the same time. Obviously that alone is hardly going to impress the discerning lady hippo (any jackass can shit himself), so to prove he's got the goods, the male will spin his tail like a shit-flinging propeller at the same time, spraying about stink and filth which will be, apparently, irresistible to some of the local women folk.