How to merge into my working copy?

I would like to pull a set of changes from a branch back into the
working copy of my current branch without affecting the index.  I
can't figure out the right combination of --commit, --no-commit, -ff,
-no-ff, --log, --no-log, --squash, --no-squash, etc... options to use
with git-merge.

Basically, I created a branch off my mainline branch a few days ago.
Made some commits on that branch.  Then went back to my mainline
branch, made a few commits there, and now I would like to make my
working copy look like a merge of its current state with the changes
from the branch, minus any associated commits.

I probably should have just used git-stash to tuck those changes away,
but I didn't.

--wpd