The whole body is covered in nerves, play and relax, use different sensations all over to find what way if affects her and she can do the same to you in return, some may make him/her giggle and twitch but each pleasure helps both partners to have fun and relax with each other to enjoy the later stages in sex even more. When a man is more relaxed, penetration sex lasts longer and remember each partner is individual and different so what did it for one may not for another, so relax and enjoy as you find out from each other.
