At nine weeks, your baby is about the size of a grape and may start sucking on his / her thumb. (americanpregnancy.org)
As soon as a baby starts sucking at your breast, an instantaneous hormonal shift is supposed to occur, telling the milk to start flowing. (rachelsremedy.com)
Each time your baby slows down, stops sucking, or starts to fall asleep, changing side can wake him up and encourage him to start sucking again. (verywellfamily.com)