There is no equipment required.
The participants form two rows, one row facing the other one. This formation symbolizes the washing machine.
One group member positions himself at the beginning of the group and slowly walks between the two rows. The washing machine "washes" the member in the course of this. The machine may perform the washing by gentle tapping, stroking or spinning. The group member may also specify at the beginning of the wash cycle whether he prefers to be washed rather gentle or whether a more intensive cleansing would be necessary.