Some of us had a chance being part of the holy sweatlodge ceremony.
The Lakota-Heeler Mitch Running Wolf introduced himself as the sweat leader in the holy ceremony
in his own sweatlodge on the Rosebud Reservation.
And of course you weren't allowed to take pictures during a holy ritual. That's why I will use a detailed description.

And who could better describe it than a Lakota?

"Whether we celebrate the sun dance or a vision quest, the inipi comes first.
It could be that the inipi was our first rite, that all the other ceremonies came later. ...

There is something holy and uplifting about the building of a sweat house. When two enemies participate in the putting up of the little beehive-shaped lodge, their old hatreds are forgotten. Envy and jealousy disappear. ...

You start by looking for the right kinds of rocks. You find them on the prairie and on the hills. ... They are called bird stones - sintkala waksu-, stones with 'beadwork' on them. ... Besides the rocks you collect firewood for the sweat bath. You use only cottonwood for this, because it is our most sacred tree. You go down to the creek and cut twelve white willow trees. We peel these sticks and plant them in the ground in a circle. ... We form them like a beehive and tie them together in this shape. The sticks form a square at the top, representing the universe, the four directions. In some cases sixteen sticks are used. These willow wands form the skeleton of the hut. They are like the bones of our people. They are coverd up. In the old days we coverd them with buffalo hides; nowadays we use tarps, blankets or quilts. ...

The finished sweat lodge reaches about as high as a man's ribs. The sweat house is small, but to those crouching inside it represents the whole universe. The spirit of all living things are in this hut. This we believe. The earth on which we sit is our grandmother; all life comes from her. In the center of the lodge we scoop out a circular hole into which the stones will be put later. ... Everything we do during our ceremonies has a deeper meaning for us and, in one way or another, symbolizes the universe, the powers of nature, the spirits, all of which are ever-present in our minds. ... The entrance to the sweat lodge faces west, toward the setting sun. Before the lodge we plant two forked sticks and place a third one horizontally across. This makes a rack against which we lean the sacred pipe. This is an altar too. ...

The man who acts as a leader first goes into the hut with his pipe. He covers the ground with sage, which is sacred. It means that the green living things, the spirits of trees and plants, are with us in the sweat house. The leader then burns some sweet grass. It is braided like a woman's pigtail. One end is lit and the smoke and sweet smell are whirled around so that it gets into every part of the sweat lodge. Thus everything is made sacred and all bad feelings and thoughts are driven out. Now all is prepared and the sweat house is ready for the people to go in.

When you enter, don't come in shorts or with a towel around you. You are going to be reborn. You'll be like a baby coming out of your mother's womb, our real mother earth. You'll come out with a new mind. You don't want to be reborn with pair of shorts on.

It's not only men who purify themselves through the inipi; women do it too, but usually they go in a group by themselves....

As you stoop to crawl into the sweat house you are like an animal crawling into his den. That should remind you that you are a relative of all four-legged creatures. As we go in, counterclockwise, the leader will sit at the entrance on the right and his helper on the other, the left side. The others seat themselves wherever they want to. We also need one man to help us on the outside. This man now brings in the heated rocks, one by one. ...

As the first rocks are passed through the entrance we say, Pilamaye - thanks. The first rock is put right in the center for grandmother earth. Then we place four rocks around the first one - west, north, east and south - one each for every direction from which the wind blows. Finally you place one rock on top of the first one - for the sky and grandfather spirit. After these first six you can pile on the rocks as you please. ...

The man who puts on the ceremony now lights the pipe and passes it around. It makes us holy and links us as brothers. You grab hold of that smoke, rub your palms with in, rub it all over your body. You pray to the Great Spirit ...

The helper on the outside now closes the flap over the entrance and makes sure that no light comes into the hut. The leader now pours, or sprinkles, water over the glowing rocks ... The water is ice-cold and the stones red-hot, so here is a unifying, the earth and the sky, the water of life and the sacred breath of spirit, grandfather and grandmother coming together ... There is a great surge of power. You inhale that breath, drink in the water, the white steam. It represents clouds, the living soul, life. The heat is very great. Your lungs are breathing fire ...

The sweat house shakes and trembles as the men sing Tunka-shila, hi-yay, hi-yay. The heat, the earth-power, it hits you. You inhale it, get filled with it. That power penetrates into you, heals you. That steam stops at the skin, but that earth-power penetrates your body and mind. ...

We open the entrance four times and let the coolness in and the light. Always we sing two songs before we open the entrance again. Four times we pour water, and four times we smoke the red willow bark tobacco, the smoke of which goes up to the Great Spirit. ...

After we smoked for the fourth and last time, we say, 'All my relatives', and the ceremony is ended. ... We leave the sweat house the way the sun travels, counter-clockwise. ... We come out with a feeling of well-being, lightheaded and happy. ...

I hope the day is coming soon when every Indian will once again have a sweat lodge standing near his house." (1)