My best friend just had her second baby and with both of them they have seemed to be really spewy and have alot of wind pains.....
with her first she didnt' really know much better but with her second she's done some research....
She has a really fast flow, so she attaches bub to get milk going; then takes her off and 'lets down' for a bit.... then puts bub back on and she gets the fuller milk at the end.
her bub also did the gulping thing (hence the fast flow) to start with; and so she found that this reduced wind pain (although its still there somewhat but alot better than it was); and she seemed more content with her feeds.
Just google it; thats all my friend did and she found lots of info. Somehow i dont think its good for a baby to be constipated for even three days i know how painful it is for me being a pregnant adult let alone a tiny baby.
How bubs poo also can tell you alot about your milk i.e if they have a lactose intolerance (from when you drink cows milk) or even an allergy to something like eggs....

all the best xxx