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1.
Injecting into skin, not into veins or muscles or anything. It is not the best way because some drugs get lost in your tissues so the effect is not as strong, and you're more likely to get absesses this way.
Yeah, his veins are all collapsed now so he's been skin popping the heroin.
by Jeweliepop February 14, 2009
 
2.
sticking a needle into your skin
A lot of druggies like skin popping
by Isayah Sanjay February 07, 2008