The brain regulates hormone secretion and is the one who commands our emotions, any point in the female anatomy can be a G-spot, with adequate stimulation, as long as the brain interprets it as exciting and pleasurable.
In that case it initiates a discharge of phenylethylamine, responsible for the excitation and of initiating the production of a neurotransmitter related to pleasure called dopamine.
The dopamine is able to make forget the problems and pains in the moment erotic.
For women to achieve orgasms this disconnection is required, hence the importance of preliminary acts. If we want our partner to get carried away we must learn the emotions that provoke the stimulation of certain erogenous zones, such as the breasts, clitoris, back, ears, among others (Explained in other of my publications in steemit)