Side glide nose up (SGNU) swim drill is just as important as the side glide nose down (SGND) swim drill. Both belong in the static posture and balanced swim drill family. SGNU builds on the skills you learned in SGND and will get you balanced and comfortable on your sides while your breathing area (nose and mouth) is exposed to the air. But you should practice SGND until you are balanced and very comfortable with it before trying side glide nose up.
No training snorkel needed for this one. Push off in SGND position. As soon as you are balanced, turn just your head until your nose points straight up and you can breathe freely. Nothing else should change when you turn your head. Don't roll onto your back. Don't lift your head when you turn it -- even the slightest lift will undo your balance. Check for good aquatic balance. Stay in this side-lying position for the length of the pool. Do this drill on both sides of your body.
If you are loosing your balance as soon as you turn your head to breathe, try the following strategy: Starting in SGND position, make sure your lungs are full of air when you turn your head to take your nose out of the water. Do not exhale immediately; instead, hold your breath in the nose-up position while you mentally check your feedback tools. Once you are satisfied that you are well balanced, exhale slowly and begin breathing normally.
1. Use the same feedback tools you would use for SGND, except that when you are balanced, your head should be in almost the same position as in the back-balance drill -- ears in the water, nose pointed straight up, and water line at the tip of the chin and crest of the forehead.
After you have spent some time with the SGNU drill with a tight-line, experiment as you did with the other static posture and balance drills -- alternate between tight-schlumpy-tight, noting the effects, , both positive and negative, of each postures. Also experiment with varying the amount of buoy pressure you need to feel fully supported by the water. As before, relaxing your posturemay erase the sensation of support.