Upside Yo' Head

I was a band geek in high school, not a jock, so I have to ask: do high school athletes wear uniforms at practice? “Uniform” in the adjective, meaning “identical or consistent; without variations in detail”. Because I’m looking at four teammates wearing four different outfits. From left to right: Earl Tatum sports a softball jersey; Ponytail Chick is in red; Summer opts for a plain white tee; and Kei$ha actually wears a basketball singlet.

I guess the kids still say “chill”, but what person under 50 70 uses “needle” as a verb? And what human being of any age would speak that line in panel 2?