I doubt this hard thrusting response you're referring to is orgasm. It might make them make a lot of noise, and it might feel very intense, and this is also when most women fake an orgasm (most women fake it). When a woman truly orgasms, her pelvic floor will rhythmically contract and squeeze and you would feel this around your penis. When a man hard thrusts me for a bit, it stimulates my Gspot and makes me very loud (and yes it does feel very intense) but that is not an orgasm.
When I orgasm, the following things happen;
At approach to O:
I sweat
My body tenses up
I breathe fast
My vagina lengthens, emits heat, gets very tight at the entrance and lubricates profusely
My hips thrust uncontrollably
There is an other-worldly kind of pleasure
At O:
As I go over the edge I temporarily stop breathing, because I physically can't, so I'm unable to make any noise until the contractions roll in.
Then after about 5 seconds of not being able to breathe, my pelvic floor contracts repeatedly, for anywhere between 20 seconds to a few minutes, depending how strong the orgasm is. The first contractions are hard and fast and close together (and feel like an explosive release), then they get further apart and more gentle as all the pent up energy is released
My legs and hips get 'locked' into position until the strongest contractions have passed
To give you an idea of how many women fake it, only one of my previous partners had ever experienced a female orgasming during PIV sex before. Every single one of my female friends fakes it (sadly), so their partners think they O every time, when actually they never do. My partner, who has been with a lot of women before me, was shocked the first time I O'd on his penis by rubbing my clit. Because he had never felt a female have an orgasm on him before. Yet every woman before me had said they had cum, they hadn't.
A female being able to O from PIV sex is rare - and its unlikely to be achieved by hard & fast thrusting.
