To severely shame and humiliate an individual in a verbal confrontation or direct insult; A powerful cut down (usually very clever or rooted in an opponents weakness); Would initiate a response from a crowd such as "dayuummm bruh!".
"Ohh sheeit bruh, that dude juss slayed his bitch ass"
To dip; to use chewing tobacco, also used as a noun to mean dip. commonly used to discretely suggest to another that the two should go to dip in the bathroom. The phrase "Slay all dayyyyy" is used by non dippers to ridicule the dippers because at one time the phrase was quite common in the dipping community and taken seriously. The word is still in use although a few teachers and administrators in the area have discovered the meaning rendering the term un-usable in their presence.
Harrison: hey man lets go slay a grizzly in the bathroom