i'm so down Share definition Flag I'll do whatever. I'm ready to do whatever you suggest. Let's get together and do something. One person says, "sup" the other says, "I'm so down" ... meaning, I'm ready to do whatever, or let's get together. i'm so down by pjmama January 30, 2018 0 0 Get merch Get the i'm so down mug. Buy Now — $32.95 See more merch