When a girl is not excited and the inner lips are drawn apart the clitoris is in most cases visible (picture 1). When she gets excited (2) the clitoral shaft increases in size, the clitoris becomes engorged with blood and the inner lips become bigger. Before orgasm (3) the clitoris retracts under its hood.
Once a girl is very excited the clitoris goes into hiding. If you’re stimulating your lover manually or orally it can then be difficult to find this sensitive spot.
Because the clitoris is very sensitive before orgasm, it can be enough to stimulate her indirectly by manipulating the hood or stimulating at the sides, making the clitoris go to and fro. Many girls like indirect stimulation of the clitoris anyway, whether they’re just getting excited or ready to climax. Ask your girlfriend what she wants, for no two women are alike.