Ejaculation may come before orgasm, during orgasm or after orgasm. It varies for different women. How much fluid is released varies from woman to woman.
Some women are unsure if they are really ejaculating or if they are urinating during sex, because at the moment of ejaculation it can feel like you need to urinate. Ejaculate is not urine, although there may be trace amounts of urine present. Felice Newman, author of The Whole Lesbian Sex Book, suggests urinating before sex to alleviate that concern.