Most babies upwards of 6 or 7 months will enjoy having their arms out of the wrap when you wear them, but when they fall asleep, this makes it difficult to ensure that the wrap provides them with head support. Cassidy (10 months) fell asleep on my back in the woods in the Santa Cruz Mountains, and I had my husband shoot a quick video of how I tuck his arms and shoulders into the wrap.
This shows a Double Hammock Carry but my technique is the same with any back carry: Get hold of baby’s hand and pull baby’s arm up over my shoulder; pull the inner/top edge of the wrap (nearest my neck) down and around baby’s arm and shoulder, then up and back onto my shoulder, letting his arm sink down into the wrap.
If your baby is laying his head against your neck or back as in this video, you don’t need the wrap to hold him or her against you. Sometimes just tucking in the arms pulls baby close enough against you to lean comfortably on you. If you do pull the edge of the wrap over the back of your baby’s head to support it, make sure that baby’s face is clear. Baby will usually lay one side of his face against you, and you pull up whichever side will go over the back of his head, leaving the face clear. Sometimes pulling the wrap up across the baby’s neck will provide support enough to keep his head from hanging.
It should be noted that he stayed asleep throughout (though he doesn’t always) and the squawking you can hear is from his two year old sister who was impatient with daddy for standing still while she was wrapped on him.