What does it mean to "ice" someone?!

Ok, so I have a question about "icing"- it has to do with smirnoff ice drink. So I had a friend who had like a smirnoff ice hidden underneath his shirt. So he had his shirt laying on the ground and had a "smirnoff ice" under it. So he asked me if I could pick his shirt up for him and hand it to him. So I did what he asked me, and I found the smirnoff ice under there. Then he was like "You've been iced! You've been iced! Start drinking! Start drinking!". I never even heard of this before. My question is: How does this work? What does that mean when you "ice" someone with this drink??