A: I regret to inform you, orgasm cannot be hurried or occur on demand in women. For many women a long amount of time is needed and then orgasm might not occur every time. Some men feel like they have failed at their part if their partner doesn't reach orgasm. If you have feelings about your partner's orgasm that you haven't shared with her, you may want to learn to talk together about this until you are more comfortable. I understand that you may become tired and I suggest that you tell your partner when you want to stop rather than continuing when your heart isn't in it. If she is highly aroused and doesn't want to stop, she might want to bring herself to orgasm. You can also help her to bring the sexual charge down by stopping your stimulation of her, placing your hand with the heal of your palm on her pubic bone and the fingers outside of her vulva pointing toward her anus and pressing firmly. The intention of both of you to cool the sexual energy down is called detumescing. Tumescence is the state of arousal.
In the Tantric teachings, non-ejaculatory lovemaking is encouraged for men. Taking the focus off climax for both men and women has value and is worth exploring for the expanded pleasure it is possible to experience when their is no goal of "getting off."