My first son was born in Japan, where the word for 'breast' is 'oppai'.  Some Japanese children ask for 'pai'  or 'pai-pai' when they want to nurse, and this became one of my son's first words!  When my second son was born, and the first one saw him nursing, he said "Oh look, Josh is having some pai! "  So the name has stuck even though we now live in Singapore, and not Japan.  It has caused confusion  in restaurants on more than one occasion as the pronunciation is the same as for 'pie' !  Also, my husband often forgets that 'having pai' is not universally known to mean 'nursing', and so he has confused many friends by saying things like "When Josh wants to sleep Kaye usually gives him 'pai'. "  They must wonder why on earth I don't just nurse him!  

Kaye Daly,
LLL (Singapore)