ASMR (autonomous sensory meridian response) is supposedly a sensation triggered by certain sounds or (whispered) words. It has been likened to a pleasant tingling in the back of one's head, but some people who experience it have also felt it as a full-body tingling. The whole phenomenon is rather new and has little in the way of full-blown research done around it, though.
I listen to ASMR videos every so often partly because I do get the tingles from certain sounds and voices, but also because they tend to be relaxing and "easy listening". There's an ASMR thread over on /wsg/ that likely has more info and "samples" (via webms) of the ASMR videos you can find on YouTube.
Yes, there are roleplay ASMR videos, and I know that can come off as weird - which is why I am glad ASMR is best experienced while listening to such videos with headphones on. And while there are not nearly as many of them, pornographic ASMR videos do exist.