This is an acronym from the Peaches Song "Fuck the Pain Away." While "SIS" probably does stand for "Stay In School" "IUD" does NOT stand for "Injustice Under Dog" as stated in the other listing for this pair of acronyms. It stands for "Intra-Uterine Device," a free form of birth control provided by Planned Parenthood. Peaches is encouraging girls to stay in school by not getting pregnant.
"IUD SIS / SIS IUD... stay in school cause it's the best."
by morebettermostrighter January 09, 2010