BT Pes 112a(5) :ידא אפגא דרגא לפחדא ידא אאפותא דרגא לשנתא‏ : (placing) the hand on the jaw is a step to fear. (Placing) the hand on the forehead is a step to sleep
See the entire entry for dreḡ, dargā n.m. stairway, step(s)