She teases her slit

Ever so gently, she slides her middle finger along her labia, from bottom to top, all the way to her clit. She licks her fingers again, adding more saliva, then there's more slip and sliding up and down, up and down. Her eyes are closed, she bites her bottom lip, but all we can look at are her fingers as they tease her slit relentlessly. After a while the movement changes, now giving a little rub of her clit at the top of each stroke, until suddenly she stops frigging herself with one finger, and uses the whole hand to cup her mound and labia, and applies pressure to the whole area.