小三小四齐步走小鸡小鸭向前看
[xiăo sān xiăo sì qí bù zŏu xiăo jī xiăo yā xiàng qián kàn]
'Xiaosan Xiaosi' translates directly as 'Third Party/Small Three Little Fourth'. In colloquial Chinese it represents the affair partner in a relationship, specifically third parties in cheating affairs, whereas little chicks and ducks symbolize innocence and purity. So the nickname juxtaposes these concepts for an odd or satirical effect.