Yes, you should oil the wick that is under the bobbin case. It usually looks like a piece of lint, but it's actually the wick. You should just put one drop of oil there, and then sew a length of stitching on scraps to make sure no oil ends up on your real sewing. I've never had that happen, but I've always stitched a bit after oiling. You may notice that it's a lot quieter after oiling.