Does ghusl become obligatory on the women if her husband rubs her clitoris (the small sensitive organ above the opening of the urethra) which causes her sexual climax WITHOUT penetration of fingers in the vagina?
Ghusl becomes Wajib (obligatory) upon both man and woman merely by penetration. If penetration has occurred then Ghusl is Wajib.
In addition to penetration, Ghusl also becomes Wajib if a man or a woman experiences a seminal discharge. A man's seminal discharge will almost always be visible while a woman's seminal discharge is mostly internal and invisible. However, Ghusl becomes Wajib upon both of them.
If the woman experiences a sexual climax with a discharge then Ghusl will become Wajib upon her.
And Allah knows best.
Mufti Ikram ul Haq
Fatwa Center of America