Hold the cob vertically over a wide, shallow bowl or pan. Using a sharp knife, slice straight down, cutting under the kernels and letting them fall into the bowl. When all the kernels have been removed, turn the knife over and with its dull side scrape the cob on all sides to extract the “milk.”
If you want more creaminess than crunch, first score the kernels by slicing through the middle of each row, before cutting them off.