Is your baby on reflux meds? I wonder if that would change poop consistency.
I am a bit confused about what you are expecting, poop wise. Yes, A breastfed baby who is pooping frequently- daily, at least-will have loose, wet, seedy, mustardy looking poops as a typical standard (there is lots of normal variation.) But a baby who is having poops that are symptomatic of oversupply or forceful let down would typically have poops that are
more wet, more frequent, more explosive and possibly, green and frothy.
After about 6 weeks of age, it is considered by lactation experts (which i am not) normal for a breastfed baby to poop less frequently-even as little as once a week or less- (some do, some don't go to such a pattern) and when it is less frequent it
has been sitting inside baby for a time and thus could be thicker and a little bit dryer-and bigger, usually. If baby is straining to poop, and poops are dry, that is constipation and not normal for a breatfed baby. And of course it would indicate a problem if baby was not gaining enough.
Have you tried techniques for dealing with forceful letdown, rather than oversupply? They are related but not the same thing, and the 'symptoms" you describe could be an issue caused by forceful letdown-and thus, just dealing with the forceful letdowm could alleviate this-
I tandem nursed a three yo and a baby but i did not give them thier own sides. I also had oversupply, and baby was diagnosed with reflux (i decided it was principally an oversupply/ffld issue. here is what worked for me- 1-I nursed baby in a more upright position-i was laid back, reclined on the couch, and baby more or less straight up and down with head over tummy and feet between my legs or angled to the side.
2-I held baby upright after nursing, for a long time. I wore him in a sling most of the time.
3) at night, i nursed side lying but then lifted baby and kind of draped him over my side so he was again head above tummy to burp him and just give time for the milk to go down. I am doing the same thing with my new baby.
4-Since my baby was gaining well, i let my older child nurse first sometimes, or nursed them at the same time and swiched sides part way through, so he got more of the fast flow and baby could hang out and nurse more relaxed with the slower flow.
I kept lots of burp cloths handy. And changes of clothes for me and babies. All my kids spit up a ton and are all the picture of health.
According to two studies, usually a mom would have to be drinking more than the equivalent of 5 5oz. cups of coffee a day for caffeine to be an issue in for baby via breastmilk. But caffeine is found in lots of things and there is a substance in chocolate that is similar.
article on forceful letdown
http://kellymom.com/bf/got-milk/supp.../fast-letdown/