she needs to be relaxed. Its easier if shes lying on her back, you will find it easier if you are at her side with your palm facing up ease two fingers into her once she is already wet. Move your hand up and down keeping your two middle fingers deep inside. Aim your fingers tips to the top of her pussy hitting a rough patch which is the g spot. Keep going and make it harder and faster until you hear her juices building up - thats when you are getting close.