to pinch and pull with a jerk and twist

to tweak someone's ear; to tweak someone's nose.

to pull or pinch the nose of, esp. gently

He tweaked the baby on greeting.

to make a minor adjustment to

to tweak a computer program.

an act or instance of tweaking; a sharp, twisting pull or jerk.

verb

adjust , jerk , pinch , pluck , pull , tease , twist