Autonomous Sensory Meridian Response (ASMR) is a physical sensation characterized by a pleasurable tingling that typically begins in the head and scalp, and often moves down the spine and through the limbs. (source: urbandictionary)
Many people experience ASMR whilst listening to whispered or soft spoken voices as well as specific types of sounds (tapping on objects, sounds of materials and more).
ASMR videos aim to relax the viewer and induce a state of calm and peace. Many people do not experience tingles but feel very relaxed and sleepy while watching or listening to ASMR.
Common triggering sounds include tapping, scratching, barely audible whispers, sand, paper. A particular sound used for ASMR is called trigger.
ASMR artists usually use binaural microphones to create a soothing, virtual experience going from one ear to the other.
For more informations about ASMR, please check these articles:
The Guardian: https://www.theguardian.com/news/video/2016/jan/04/the-asmr-videos-that-give-youtube-viewers-head-orgasms-video
Vice : http://www.vice.com/read/asmr-the-good-feeling-no-one-can-explain
Soy Noticia 4, ASMR (episode where I appeared): http://www.cuatro.com/soynoticia/temporada-1/programa-6/mejor-Noticia_5_2151000006.html
You can also check my ASMR playlists to find your own trigger:
No talking Playlist: https://www.youtube.com/playlist?list=PL1ozOHxllQ2TMaJXRbSIMpPlJqK1nxp6v