My first exposure: I was "flipping" through Twitch channels and came across one of some woman leaning into a mic right in front of the camera making stupid sounds. I sat perplexed for a minute, looked at the viewer count, and was like "why on earth are 3,000 people watching this and why did homeboy just gift $300?!?!".
Then the woman stood up was built like a supermodel and wearing tights revealing damn near everything and I said "oh, that's why".
Promptly went back to watching that cooking stream they have now.