FlyerBookmarks - infant sleep sack A sleep sack is basically a sleeping-bag for an toddler or infant. They are seen to be a greater as well as less dangerous option to sheets of baby blankets within the baby crib, which may lead to deprivation of air. A toddler sleep sack can even be convenient to the child to settle in since they stay in put. Sun, 25 Dec 2011 00:29:14 UTC en