This is the primary practice that the Sufi poet and mystic Rumi explored with his beloved friend Shams during their intensive retreats together.  The practice has perhaps been most graphically presented in images of the quintessential Hindu lovers, Radha and Krishna, bonded together as one through the shared connection of their gaze.

Gazing Raptly

The basic manual for this practice is the hardbound Rumi, Gazing at the Beloved by Will Johnson (Inner Traditions, 2003) which has been re-released in paperback as The Spiritual Practices of Rumi (Inner Traditions, 2007).  The book is also available in a French translation as Rumi, union des regards, fusion des âmes (Editions du Gange, 2005).
        
The supplemental manual for this practice is Rumi’s Four Essential Practices by Will Johnson (Inner Traditions, 2010) which includes gazing raptly along with eating lightly, breathing deeply, and moving freely.
 
if you want to know God,
then turn your face toward your friend
and don’t look away

         Jalaluddin Rumi

While even a few minutes of this kind of intimate contact can refresh and heal, friends are also urged to explore the practice for longer periods of time:  minutes turn into hours, hours can turn into days.  Over time, your conventional sense of self—with its created notion of feeling separate from everything it perceives to exist outside of its residence in the body—starts dissolving away, revealing the mystery that’s been hidden underneath all this time.

One of the central techniques of Embodiment Training is an interactive gazing practice from the Sufi and Tantric traditions that you explore with a partner.  Friends will sit down together, look into each other’s eyes, hold each other’s gaze, relax…, and simply surrender to the parade of sensations and perceptions that spontaneously begins to occur.