Within the 21 Lessons of Merlyn, this ritual is said to create a physical portal into the Otherworld, through which a person can literally walk.
The Incense recommended in the book is Threshold Smoke (Listed on this website as Threshold Smoke, Formula #1)
1. Place your Stone Circle, Clockwise. There should be 8 or 12 pieces. I believe Preseli Bluestone would
be best, but this is not necessary. You should have a Talisman consecrated to Janus (the text suggests a
Rod made of Beech Wood in his likeness), the Roman God of Doorways, within the Circle. However,
This need not be anything so elaborate, in my experience: A small image or drawing of Janus that you
have consecrated to him would be fine. The purpose of this Talisman is to function as a Guardian,
keeping other spirits from using your Portal.
2. Be seated within your Circle. Speak the Grand Invocation:
To Bathe in the Waters of Life,
to Wash off the Not Human,
I come in Self Annihilation
and the Grandeur of Inspiration.
3. Now, recite the Charm of Making Three Times in rapid succession:
ANAIL NATHROCK
UTHVASS BETHUDD
DOCHIEL DIENVE!
This means, "Dragon's Breath, Spell of Life and Death, Thy Charm of Making!"
More information about this can be found here.
As written, the Charm is pronounced,
"Ah-Null Nah-Th-Rock Oo-Th-Vass Beh-Thud Doh-Chee-El Dee-Ehn-Veh!"
NOTE: "Ch" sounds like the Scottish word "loch".
4. Now, spend some time (about 15 to 30 minutes) in your Circle, waiting. If you see a patch of fog that
appears brighter than the rest, that is the Otherworld Portal. Douglas Monroe advises extreme caution,
should you decide to enter it, as people have, apparently, been trapped doing that.
My personal experiences with this rite can be found here.
A personal variation of this ritual, produced through more recent contemplation and experimentation, complete with my experience, can be found here.