|Make sure everything is as flush as you can get it to avoid leaks.|
|I have to push the white part of the tubing down from the other side to ensure it's flush.|
|Having an air tube makes it easier for baby to suck the milk out. You can leave it closed if you want baby to work harder (building up a milk supply.)|
|Release both tubes. (Unless you're leaving the air tube closed.)|
|I hold the bottle like a phone against my neck. I can HEAR the bubbles as the milk is flowing. If I don't hear it, I check the position of the tubing.|
The best instructions I've found for using the SNS are here.