There are actually two traditions of Tantra: the Taoist, coming from China, and the Vedic, from India. .
The Taoist Tantra approach was very practical. It was developed as a way for the Emperor to have the energy to satsify all his concubines as well as rule a large empire. There were prescriptions for how often one should ejaculate,, considering it as life force that must be preserved for energy and vigor. They were fairly ascetic: three times a week for a man in his 20s, once a week in his 30s, once every two weeks in his 40s. There were positions and thrusts designed for prolonged initercourse. .The famed “Taoist thrust” is 10 shallow then 1 deep and 9 shallow then 2 deep and 8 shallow, etc. There were also exercises of stretching he dick that were prescribed.
Vedic Tantra is more spiritual, with the association of the genitals with different deities, and seeking enlightenment through their union in ecstasy. There is a stronger emphasis on the connection and union of the couple, with exercises to develop greater familiarity with the feeling,, smell and taste of the different parts of their bodies. Intercourse itself is supposed to ultimately manifest in what would feel as a strong intimate energy flow between the partners. The practice should enhance the feeling of bonding while at the same time feel serene.