Incantation:

i irhab i irhab gidime i irhab
gidim igibar i irhab girgiammake
igibar igibarbar gidimmake

Ritual:
You crush moldy wood and fresh leaves of Euphrates poplar in water, oil, beer and wine. You dry, crush and sieve snake-tallow, lion-tallow, crab-tallow, white honey, a frog that lives among the pebbles, hair of a dog, hair of a cat, hair of a fox, bristle of a chameleon and bristle of a red lizard, claw of a frog, end-of-intestines of a frog, the left wing of a grasshopper, and marrow from the long bone of a goose. You mix all this in in wine, water and milk with the amhara plant. You recite the incantation three times and you will see the ghost. He will speak with you. Look at the ghost - he will talk with you.

(BM 36703 ii 11'-23', ed. I. Finkel AfO 29 (1983-84), 10)
Finkel says of the incantation: "(it is) left untranslated (as) one of those obscure magic passages often explained away as mumbo jumbo, with the proviso that garbled Sumerian may be involved"
Most of the ingredients are probably blinds for plants and minerals, since "lion-tallow" is well-known as a euphemism for "opium." The fourteen exotic ingredients may be substituted for by other well-known psychotropics and fixatives. For instance, Amhara is thought to be a species of Euphorbia, used as an emetic and purgative. I have found tobacco to be a satisfactory substitute as an unguent prepared in butter.
I've tried it once before bed and found it worked to invoke the ghost I needed.