The sign for "prefer" is also commonly called "favorite."
You use this sign in sentences such as, "My favorite website is
Lifeprint.com."
PREFER / FAVORITE /
RATHER /
FAVOR:
Note: the middle finger "jabs" into the
chin (gently) it doesn't stroke the chin -- it pokes (jabs) twice similar to the motion
of tapping the spacebar on a computer.



Here is a side view:




Notes:
If you do this sign on the lips, it generally means "taste."
On the sign for "taste," some people just bring the tip of the middle finger
close to the lips without making contact.
While the sign PREFER / FAVOR can and does also mean "rather" there is another way to sign prefer
or rather that doesn't mean FAVOR or FAVORITE.
See:
TASTE
See:
RATHER