Aww I dont want it to be more painfull then it should be
My pregnancy books say your have to stimulate your nipple for a few hours a day (3/4), twice a day and this will release oxytocin and bring on contractions. But labour from nipple stimulation can be longer and more painful
I read diffrent storys some say it starts aftrr 15 min some as you say day or 24 hours
They say for it to work you have to stimulate your nipples for a whole hour several times a day for several days. So like a total of 24hrs ovwr a weeks period time (4x a day roughly) and it has to be enough for you to climax so your uterus starts contracting.