Getting SNS bottle ready
Start with a clean SNS bottle and cap. You won't need the string that came with the bottle, so put it away in a drawer somewhere.
Empty the tubes of any water by squeezing the empty SNS bottle with the cap on. If you don't have a cold, you can suck on the tubes to get rid of the water, but it's true that you can be producing cold germs before you start having symptoms.
Find a rubber band, and put around base of SNS bottle. There should be enough tension so that it will hold the air tube in place (see below), but not so tight it constricts air flow.
Fill SNS bottle with milk and screw cap on.
Keeping SNS bottle upright, take one tube, I call this the AIR TUBE, and leaving a little slack, close off by pushing down into a groove.
Take that same tube and secure against SNS bottle by using the rubber band, making sure that the end of the tube ends up near the base of the SNS bottle. To avoid slack, you have to coil some of the tube under the rubber band. (See figure 1)
I call the other tube, the MILK TUBE. It doesn't need to be closed off once you get the hang of things, but in the beginning, you should. The following instructions assume that the milk tube is closed to start with.
Set SNS bottle aside (upright) within arm's reach.
Latching on
Get baby ready. A lap cushion or Boppy, a towel under baby's head to catch spillage, and a footstool to raise your knees slightly above your hips, are helpful. If the available footstool is too high, just move it farther from your body. As usual, it's best if the baby's not screaming, and you've woken him up to feed when he's starting to make intermittent hunger sounds in his sleep, rather than when he's already become ravenous.
Grab SNS bottle and place on its side near baby's head, making sure that the milk is down at the cap end.
Open milk tube by releasing from groove.
Take milk tube and see if you can get baby to latch on to both the breast and tube at the same time. Aim tube end so that it is near nipple tip. Tube doesn't even have to be touching nipple or breast, baby's mouth closes and brings them together. The best length is when the tip of the tube is flush with or protrudes just beyond the nipple tip. The best position is when the tube is at the roof of baby's mouth, rather than at the tongue-side.
Alternatively, let baby latch on first, then thread the milk tube into his closed mouth. The best place to try is the corner of his mouth. Place finger of one hand against corner of mouth and pull up, exposing some of the nipple. With other hand, point tube end in direction of nipple tip, and give a quick push past the resistance of the baby's gums.
Alternatively, tape the milk tube to the base of the nipple, so that the tape and the tube are at right angles. Sometimes longer is better (tube end protrudes beyond end of your nipple), but the tube becomes more likely to slide off the side of your nipple and lie flat beside the nipple (no good). Sometimes shorter is better (tube end is flush or shorter than nipple end), but the tip of the tube can get buried in the flesh of your nipple and cut off flow. (I've cut the tapered tip of the tube and made it straight, that seems to work better for me. If you don't like the result, you can always use a razor blade and make it tapered again.)
If you were able to position the milk tube correctly inside the baby's mouth, you should have seen milk come down the tube immediately.
Getting the milk to keep flowing
If the milk tube was positioned correctly inside the baby's mouth, you should have seen milk come down the tube immediately. After the baby sucks a few more times, a vacuum forms inside the SNS bottle, and it gets harder and harder for baby to get milk. Now open the air tube. If the milk tube had been positioned correctly, you will hear a bubbling sound, and you will see bubbles rising up inside the SNS bottle, as air enters the air tube and dissipates the vacuum.
If you don't hear or see bubbles, then you need to start over with positioning the tube.
How to know the milk is flowing
The milk is flowing if you feel cold milk on your nipple every time the baby sucks. (See exception to this rule in Advanced Tips below.)
The milk is flowing if you see bubbles forming rapidly and rising to the top every time the baby sucks, and bubbles at a slow rate, when the baby is pausing between sucks.
The milk is flowing if the air tube is free of milk, or the milk in the air tube is moving back into the SNS bottle.
One test is to turn the SNS bottle right side up for a moment and see if the baby sucks air into the milk tube, but the baby will end up ingesting some air, so I don't recommend this method.
Another test is to close the air tube, wait a few sucks, then reopen it to see if you get a burst of bubbles like you did in the previous section.
Sometimes, the milk will flow even though the tip isn't in the right place. This is when the tip is in the mouth, but not in the suction path, and the milk flows continuously with gravity. Usually, you don't want that. You only want the milk to flow when the baby sucks. Otherwise, the baby will gag. Signs that the milk is flowing from gravity is that bubbles will be forming rapidly even when the baby is pausing, and the milk will tend to dribble out of his mouth. The milk tube is not in the right place if the tube comes out of his mouth when you pull gently. In the right position, baby's gums will be clamped down on the tube, and there will be resistance to pulling the tube out.
However, if the baby's screaming and you just can't get the milk tube in the optimal position, to heck with it, let the milk flow with gravity and the baby take big gulps. Slow down the flow rate by lowering the SNS bottle so he's not gagging. You can either try repositioning the tube when he's fed a little and calmed down, or just let things be.
What to do if the flow seems to have stopped
Push the tube further in to baby's mouth, or pull out slowly, or twist in place to see if you can re-establish flow. Usually, this doesn't work, and you need to start over with latching/inserting tube tip.
A clogged tube is never the reason for stopped flow in my experience. So don't squeeze the SNS bottle. It just makes the baby gag and doesn't correct the problem
However, squeezing the SNS bottle gently can be useful if baby is falling asleep at the breast, and a little bit of unwanted milk wakes him up and makes him drink some more.
Sometimes, the air tube has bits of water in it from the last cleaning, and can keep the air tube from working. Make sure air tube is clear of water.
Avoiding milk leaks
FIRST RULE--If you're new at this, at first sign of leak, turn SNS bottle upright. This is always the first thing you should do. This will limit amount of leak to whatever is in the tubes.
Next, hold end of milk tube straight up into the air, and wait for milk in the milk tube to drain mostly back into SNS bottle. (figure 2) As you get practice, you turn the SNS bottle upright and raise the milk tube at the same time.
Finally, close both tubes. Now you can do anything with the SNS bottle without having it leak.
Sometimes, overtightening the cap causes the tubing piece to be crooked with respect to the cap end disk, and milk will leak from there. Make sure the cap end of the tubes are centered in the disk holes when tightening the cap.
SNS Bottle height
SNS Bottle height works when the level of milk in the SNS bottle and tip of the milk tube are close. When the milk tube is optimally positioned in the suction path, SNS bottle height isn't too important. But when the milk is flowing by gravity, if the SNS bottle is too high relative to the tube tip, milk flows too quickly, and makes the baby choke. If the SNS bottle is too low, air enters the milk tube, plus milk tends to leak out of the air tube. In other words, the milk tube acts like the air tube and the air tube acts like the milk tube.
I tend to rest the SNS bottle on its side, on the cushion the baby's head is on so that the cap touches the baby's head.
Advanced tips
Once you get used to using the SNS, and learn how the air tube and milk tube work, try feeding the baby with the air tube closed off. If the tube end is in the suction path, the baby can still suck with enough force to draw milk from the SNS bottle against the vacuum for several minutes. Towards the end of feeding, or at times when the baby needs to satisfy his sucking urges rather than feed, the baby can prefer the slower flow. When you do this, you won't be seeing bubbles any more, so you'll have to rely on other clues that the milk is flowing. That's why it's better to wait to try this until after you've had lots of practice feeding baby with the air tube open.
If you're feeding with the air tube closed, you need to open the tube to release the vacuum every few minutes, and close again. Experiment with amount of time the air tube is open. Sometimes the baby will dislike the sudden rush of milk that occur with a full release of vacuum. Closing quickly will release the vacuum partially.
Once you're an expert feeding the baby both ways, with the air tube closed and open, you can go back and forth between the two. As another example, you won't need to coil the air tube under the rubber band right at the beginning. If you start off feeding with the air tube closed, you can do the coiling after the baby has fed a few minutes.
If the milk tube is positioned over baby's tongue or side of mouth, the milk tube can get sucked further and further into his mouth towards his throat, until he coughs. If this keeps happening, you'll have to keep hold of the milk tube while he feeds to prevent this. Sometimes you'll know the tube is migrating further into his mouth because you won't feel the cold milk any more, but you know from other signs that the milk is still flowing.
One reason you might want to feed some of the time with the air tube closed, is to encourage the baby to suck harder, if you are trying to establish your own milk flow.
SNS-ing in bed
Yes, you can SNS lying down in bed in the middle of the night! But don't try until you're already an expert SNS-ing sitting up.
You need a bright nightlight to provide some background light for the duration of the feeding, and also a good flashlight for initial tube positioning.
You also need to work out how you want to position your body, your baby, the SNS bottle and pillows. I lie on my right side, on top of an old flat pillow to raise my upper body so my right nipple is at the same height as my son's mouth. My right elbow is above my son's head, my right forearm under the second pillow for my head. The SNS bottle is on its side, also under the second pillow with the air tube on the upper flat side of the bottle.
The hardest part is trying to get the milk tube into the mouth in the dark with just one free arm. One thing I do is try jabbing the milk tube end into the corner of the mouth and listen for the bubbling.
Be prepared for some spillage. Lie on top of a towel. Try not to fall asleep, because inevitably, the tube pops out of the baby's mouth and you wake up an hour later with a cold wet patch below you.
Cleaning tips
There are 3 known ways to clean the SNS tubes. Hot soapy water, vinegar, and boiling. Since I'm paranoid about residual soap, and vinegar leaves a smell for a long time as well as not working that well on grease, I prefer to boil.
But a fourth way that gets rid of accumulated gunk is to thread a thick embroidery needle with several skeins of embroidery thread and gently work it through the tube to the cap. Squeeze and rub the tube against the needle and thread as you go. Make sure the thread is long enough so you can use it to pull the needle back out. Be careful as you advance the needle not to poke the needle through the tube wall. I ruined one tube that way.
Final Note
I wrote these notes because I couldn't get the SNS-ing to work for me using the instructions that came with the bottle. Trying to get the string around my head, long hair and glasses, trying to get the tape to stick to my breasts if it ever came off because wet milk keeps fresh tape from sticking, trying to cut the tape with the dull edge of the rinky-dink tape dispenser, trying to figure out if my son was drinking any milk, milk leaking everywhere, all with an increasingly frustrated crying baby on my lap, I cursed the manufacturer. When I heard the story of a mother who flung her SNS bottle at her husband who came home and asked how she was doing, I completely sympathized. Some people do fine with the original instructions. But if it doesn't work for you either, try giving my way a try. Also, even if my way doesn't work, I do give tips on how to know when your baby is getting milk that shold be useful no matter how you use the bottle. Good luck!