Do I have any scientific research on it? No. :-( I'm actually dismayed that there isn't more scientific research on this sort of thing. But it makes sense: merging consciousness is a deeply personal thing, far beyond physical nakedness. Without a proper context ("set and setting") one's own inhibitions will prevent it, or prevent one even thinking about it.

I learned about it from (and I swear I'm not making this up) a pamphlet I ordered by mail out of the back of a comic book on "How to Read Minds". Much to my surprise, the simple technique it described worked. It turns out that thoughts are in a kind of space around us and the same faculty that we use to perceive "our own" thoughts can just as easily be used to perceive the thoughts "of others". In fact we don't have thoughts of our own, no one does, no more than a TV set has TV shows. Your brain has an ability to "tune" thoughts in and out, but they exist separately from us ourselves.

Cf. Kurt Gödel's description of how to "perceive pure abstract possibility" in http://www.rudyrucker.com/blog/2012/08/01/memories-of-kurt-g...

Now the sharing of thoughts deliberately (forming a thought and "sending" it to someone who is primed to receive it) aka "telepathy" is different than the merging of two consciousnesses into one consciousness. In fact there is only one consciousness, it is unitary, and the belief in separate identities is a perceptual structure founded in the ambient thought-forms. Separate identity is an illusion. So "merging" is actually a remembering of what is already the case, you just weren't paying attention.

There is one thing I can point you to: Dr. Charles Tart wrote a paper "Psychedelic Experiences Associated with a Novel Hypnotic Procedure, Mutual Hypnosis", but he's pretty woo-woo.

Anecdotally, lovers sometimes report merging during intense lovemaking. Many spiritual groups (associated with a religion or not) will tend to experience it during holy rituals. One indicator is group synchronicity.

The deepest experience of "one being looking through two pairs of eyes" is very rare, apparently, but lesser manifestations are pretty common.

In any event, if you can find a partner that wants to explore this with you, the technique is ultimately simple: Create the "set and setting" (peaceful, quiet, free from interruptions and distractions, and dedicated for the greater good of all), look into each others' eyes, and lower your inhibitions. That's it.

There are other factors that can help: breath together synchronously. Some people enthuse about cannabis or MDMA, etc., but they are not necessary, avoid them is my advice. Then again, if a glass of wine or a joint helps you relax and get cozy there's little harm.

What you're doing is forming a direct mutual feedback loop between your body/mind and the "other" person's body/mind. With practice and love this loop deepens until there is literally one organism in two bodies, carried by the feedback loops between the two nervous systems et. al.

I could go on, but that's either enough or too much already, eh? One thing to remember if you're going to experiment with this stuff, do it with utmost integrity. Just as Gödel said, "The ultimate goal of such thought, and of all philosophy, is the perception of the Absolute." Your ultimate goal must be towards the good.