Joining is like this: I work with 5 beautiful little children who have autism, aged 3 to 7. Some of them have behaviors which we call "isms". For instance, one of my children, N, does an ism where he paces/prances around his room holding a shirt in his hand. He waves the shirt in intricate and fascinating and repetitious patterns back and forth and up and down, and he studies the shirt and the carpet upon which he is pacing/prancing/dancing with enormous concentration and focus. While he's doing all this he vocalizes--usually sounds that we generally can't understand to be words. Sometimes N can ism for 45 minutes without a break. Sometimes for 2 hours. It used to be that he wouldn't look at anyone at all while he was doing that. Now he tends to glance over regularly while he's isming.
His parents used to use a program for helping N. called ABA. That program called for the parents to do their best to stop N from doing the ism--they would interrupt him, physically manipulate him, very insistently demand that he do what they wanted, pay attention to them, etc. etc.
Now his parents use a program called the SonRise program. I am part of the team of volunteers who works with N. When he isms, we join him. We carefully observe his behavior, and try to understand what he is getting out of it--why does he enjoy it so much--by doing it with him--sometimes on the other side of the room, and sometimes closer. We match him step for intricate step, wave of shirt for intricate wave of shirt, vocalism for vocalism. We do this with delight, as he clearly delights in it. We do it with joy and energy, because we are doing our absolute best to say to N "If you are unable to come into our world, then it is our delight and privilege to join you in your world. You rock and we want to be with you."
We are being kind to N, and in so doing, because we love him and love being with him so much--we are also being kind to ourselves. N's parents really rather disliked the ABA program they were using before, but they believed it was the best thing at that time. In finding the SonRise program, they have grown in their ability to be kind to N and kind to themselves. They and N are in the process of growing in their ability to be kind to themselves and others. I find this is a brilliant beautiful amazing delight.