The expression You really slay me! dates back to American English of the 1920s so it is fairly traditional slang these days. You might even seem a bit quaint if you used it. But there is a new way in which slay is being used adjectivally, as in He is so slay! That movie was slay! Or as an interjection. What do you think of the movie? Slay!
ZG: 5
As with all such slang it has huge currency in a particular group.
Read More