I got the first 6 inches in by stuffing it, but then realized that I needed another technique. I figured out a great way to do it, which takes advantage of the flexibility of the insulation. I'll try to describe it here...
Put the first few inches on as above, then grab it with both hands. Squeeze tight on the tip of the hose, through the insulation, then squeeze loosely with the other hand. Stretch out the insulation (1/2" or whatever it will do) and then squeeze with the hand that was previously loose. Then loosen your grip with the other hand. Alternate back and forth by compressing and stretching the insulation and using this motion to either move the hose with it (stuffing) or let the hose slip inside (stretching). Once I got the hang of it, it took only a minute to do.