Get yourself two mirrors, preferably one big enough to see your whole body. Now when you're doing this ritual, don't try to record evidence of it with some kind of device because it won't work. But, you see I can prove to you that this is real. Because this ritual doesn't require much out of you.
Put the two mirrors between you, facing each other so that they reflect off one another. Adjust the space between the two mirrors so you can see as many reflections as possible.
Now stare at yourself through one of the mirrors but don't smile, just keep up a serious or a sad face. Eventually after some staring you will realize that one of your reflections will be smiling. But only moments after your realization, it will look just like a reflection of you.
Now the ritual is done. Wherever you go, when you pass by a reflection of yourself, you will notice that your reflection will be smiling. If you're a quiet man like me you'll dismiss it. But one day it will eventually break you apart and you will realize that there is nothing wrong with your reflection and that you are actually smiling.
During the ritual you brought something to our dimension and now it's with you forever.
Whenever you see yourself in a reflection smiling for no reason whatsoever, don't be confused.
It's just the man from the other dimension smiling at you.