I read on a few websites that frothy poo can be caused by too much foremilk. DD (13 weeks EBF) is having very frothy poos. I always let her come off one side by herself then offer it again before moving her onto the other side which she sometimes takes, sometimes doesn't. At the next feed I always put her either on the boob she didn't feed on last or the one she fed the least off. She usually stays on one side for at least 15 mins usually more (up to 45 - I get to watch A LOT of telly 
Could I do something differently or am I wrong about the frothy poo and should stop worrying?
Advice please oh wise ones