It finally occurs to Alistair that Cullen's making himself comfortable in a way that indicates he'll be sticking around after Alistair falls asleep. He probably ought to protest, but...it's not like he wants Cullen to leave.

Far from it.

He attempts a firm nod -- though it's not really stable enough to qualify as such -- and lets his eyes fall closed. Still awake, for now; just resting.