Stimulating Anterior Fornus can achieve pretty fucking intense orgasms internally. Stimulating the upper portion of the vaginal wall, in turn stimulates the clitorus and causes orgasm, again internally.
A lot of women do have a harder time with it. Primarily, I'd imagine, because sexual education is lacking in the practical application department and boys are stupid.
All the same, I've made partners orgasm without involving the clitorus or the genitals at all. Manual and quite often oral stimulation of the nape, breasts, navel, knee, and the arch of the foot.
Arausal and release are definitely not localized to the clit.