I have been pumping at work for three weeks now. Everything seems to be going well - I produce enough milk or even slightly more than needed which I've been banking.
I achieve initial letdown fairly quickly and pump until each breast is as empty as possible. I will apply a gentle pressure to each breast to facilitate this.
At the end of my pumping session, I'll often experience a tingling in my nipples and then milk will spray out like crazy. It almost hurts because it seems every duct is active at once. It only lasts about a minute.
What is this exactly? Should I stop pumping before this happens?