The alignment of your nipple in the flange is very important. If it is not perfectly aligned, your nipple may rub against one of the walls when it is sucked into the tunnel. This can cause discomfort or irritation, and/or decrease your production.
Your nipple should be centered in the opening of the flange, without touching the walls of the tunnel.
A few tips to perfectly position your nipple in the nipple shield
By bending over and letting your breast hang, you will have a better visibility to position your Perifit Pump on your nipple. Here's a video showing how to do this:
You can also remove the shell of your Perifit Pump, and position the rest of your breast pump (see image below) on your breast. The transparency of the parts will allow you to have a better visibility. Once well positioned, you can clip the shell.
Don't hesitate to use the flange alone to practice positioning it. With practice, you'll feel more comfortable positioning your breast pump.
If you are unsure of your correct flange size, please see “How do I know which flange size to use?”