no, not like those other phrases. Think of drifting as you are in a canoe on a lake, but not paddling. Just drifting on the water, not thinking about where you are going and not making any effort. To drift off to sleep is to lie down, not think of anything, and sleep.

Thank you very much! :)

In effect the same, but the emphasis here is the "drifting" a sense of lazy, gentle, lacking in effort. People do these things in different ways. Not always meaning the same scenario for all. . Thinks Summer day, lieing in the warm field, not a care in the world, ...your eyes are getting heavy, you close them, When you awake you will feel refreshed. I will snap my fingers, ...