"You never enjoy the world aright, till the sea
itself floweth in your veins, till you are clothed with the heavens
and crowned with the stars."
Thomas Traherne
An attunement is a procedure by which your personal
frequency is lifted up and gets attuned to the receiving and passing
on of a much greater amount of life-energy, Reiki. You will not
be re-connected with the universal Source as sometimes is stated,
since you always were (otherwise you would be dead), but a much
better connection will be made which serves as a spiritual awakening.
During an attunement the Reiki symbols are planted in your aura
and several chakras.
Often the comparison with a radio is made: As an energetical being
you are sender/transmitter of waves like a radio; if you wish
to listen to good music (positive, healing vibes) you have to
make sure that your radio is well attuned to the right station
(the life-energy you're interested in), otherwise you'll get a
lot of unwanted noise and poor quality of music (energetical blocks
preventing the Reiki from properly working).
The cause for the distorted transmission of universal
energy in most human beings is the illusion of separation. It
is the idea that we are separate, unworthy beings, not deserving
love, having fallen out of divine grace, being attacked by others
and therefore defending ourselves against other separate human
beings. The result is that we energetically 'close the door' which
means that we close our chakras and put our auric shields as a
tight coat around us.
But this is a most inappropriate defense, since we not only keep
the unwanted out of our energy system, but are also unable to
let the good things in. A second problem is that a closed down
energy system is unable to properly transfer energy, which leads
to the forming of blockages. Blocks or blockages are stored amounts
of energy, mostly of low vibration, developed as result from negative
thoughts - beliefs - emotions - experiences, and often leading
to pain and disease.
If you are energetically spoken 'open' you can let go of painful
emotions and work through negative life experiences without getting
damaged psychologically. If you are energetically closed you tend
to get stuck in negative experiences and stubborn beliefs. Since
life is change and requires transformation, you harm yourself
with mental, emotional and spiritual immobility.
The way back to health in a broader sense is clearing up your
energy channels and reconfirming your connection with the divine
source in and around you. And this is exactly what a Reiki attunement
does.

Japanese draught-screen 16th century
The above makes also clear why meditation, yoga,
other spiritual practices including spiritual sexuality are helpful
in raising your frequency and becoming enlightened:
Through all these modalities you can experience limitlessness,
oneness, union with the All, nothingness, total acceptance of
life, total love, happiness, ecstasy. In the high vibrations which
accompany these experiences of wholeness, blocks and karmic patterns
are simply burned or released, because there is nothing in your
being they can hold on to anymore. You have changed.
A Reiki attunement works exactly the same and is therefore a powerful
healing in itself.
Reiki attunements work must faster than other spiritual practices
however (unless kundalini breaks through): your frequency immediately
lifts up with an attunement and you can start channeling healing
energy. Next working with Reiki, by preference daily, will only
help you to get even better attuned by allowing positive energy
to run through you. Remember: with Reiki always both the healer
and healee get healed!
Attunements can only be given by fully initiated
reiki-masters, and of course by highly spiritual human beings who
are probably enlightened. After all dr. Usui received the gift
of Reiki in a satori and he was a very spiritual person.
But to be sure of a well performed attunement I suggest you approach
a Reiki master/teacher; there are many of them nowadays. Often
a bond of confidentiality grows between master and student and
therefore it is best to find someone you feel safe and comfortable
with.
Why would you need a Reiki master for attunements? Well, they
have received the energy, studied the system and the ethics, they
are supposed to work on their own further spiritual growth, and
therefore they should be able to assist you on your path to wholeness.
They have allowed themselves to open up for the gift of universal
love and healing and they can pass it on to you. What you do not
have, you cannot give. But once you know real love and goodness,
the only thing you want to do is spread it further. So if you
send out thoughts of finding a good Reiki master I'm sure the
universe will answer you.
Traditionally attunements are given in person, and still many
Reiki masters and students prefer this way of working. The last
years however the system of distance attunements has been developed
as a logical extension of distance healings and the distance symbol.
Attunements in person and distant attunements are equally valid
and powerful.