this is an excellent question and one that comes up often. my suggestion is to take a clean q-tip and dip it in the nystatin. then paint one side of the cheek. use another clean q-tip and do the same for the other cheek lips tongue etc. i would recommend using the nystatin until the thrush is no longer visible to the naked eye -- and then use it for two more days.
my 11-month-old was prescribed nystatin when he got thrush. how should i use it and for how long?