Bangkok has its lady boys but the Amazonian town of Manaus has peixe bois. If it sounds like a slur on someones manhood, it is. Peixe boi means &lsquofish cow&rsquo in other words, the gentle manatee. The aquatic mammals once thrived in the Amazon but when the rubber economy collapsed, Manaus went without electricity, and manatee fat burned in the city&rsquos lamps. That&rsquos what they told me. But they also said that the manatees&rsquo cousin, the boto or river dolphin comes ashore to light up the nights of local women with &ldquothe best sex in the world&rdquo. No wonder there were no botos at the souvenir shop. My peixe boi cost me 15 reais.