Abbreviation for "She'd Get It". Referring to a member of the female sex that one would like to engage in sexual contact with. Can add other letters to specify intended course of action (SGIB- "She'd Get It Bad"),(SMGI- "She'd Maybe Get It")
(Girl Walks by)
Bro 1: "SGI"
Bro 2: "Oh yea, def."
Bro: "See that girl over there? SGI"