in this case "dirty" means that it has a vanilla cream flavor added.
it's the fad right now. taco bell has some drinks like this. i think it might be just a pepsi company thing.
anyway, my brother discovered a 20oz dirty mountain dew at wal-mart a few days ago & we got one to split.
it has a vanilla-y smell & a lemon-ish taste with a bit of vanilla. not horrible. and not something to get again.
