Penetrate as deeply as you can and at the same time let it be a “porous” contact, remembering that pushing unduly hard against the vagnal walls will negate this magical sensitivity. In Tantra, which ever position you are in, the idea is to allow the bodies to remain together or move as a single unit, keeping the penis and vagina as an unmoving focal point. When we keep this in mind, the bodies themselves find creative positions around the genital connection.
The thrusting pelvic movements in regular sex are generally done in opposition to each other; you pull away from and then push towards each other at the same time. Backwards and forwards you move, forcing the penis in and out of the vagina without any time for real correspondence between them. But in Tantra, when you move as a unit, the penis does not leave the vagina. It stays all the way within the depths of the vagina, and the bodies rotate and move around this primary connection, each position contributing to sexual exchange. The thrill of these rotating shifts in position easily replaces the pattern of thrusting and friction-like movements in sex. Men will also find some succulent movement is possible within the vagina without actually moving out or creating any friction, and this is delightful.
The Heart of Tantric Sex
Diana Richardson 2003