Dude I know lol. It's was the culture of early 90s rap music from Houston that popularized it. Swisherhouse , with Paul wall, bun-b, slim thug, Mike Jones, big Moe, DJ SCREW, and a bunch of other artists gained notoriety with chopped and screwed rap music.
Basically you take a track and slow it wayyy down and cut in up. And it sounds like absolute shite unless you fucked up on something. Lean and screw music started out as an underground phenomenon. But it's the same shit as the pill.
It's just way way cooler to pour it up and sip on it. It's like walking around with a IV drip. If you get too throwd you stop sippin. Losing your buzz sip some more.