Autonomous Sensory Meridian Response
ASMR is a feeling of well-being combined with a tingling sensation in the scalp and down the back of the neck, as experienced by some people in response to a specific gentle stimulus, often a particular sound. This can be sounds that reach back to when you were a kid or had a special pleasing experience while growing up. But isn't it kind of sexual, this ASMR thing?
I cannot imagine falling asleep while watching a video, so this is kind of counterproductive. I read, only 10% of people report feeling aroused by ASMR, so any feelings of arousal might be due to the intense relaxation and personal attention. Close your eyes (or keep them open, I don't mind) and put your headphones on. This is my only advice.
There's more by ASMR Amy and I can totally recommend to check out some more videos, too.