Sci-fi book I read as a child about interdimensional travel through an out-of-body-experience

If I recall correctly, a young boy would contort his body and/or limbs into nearly impossible postures which triggered an out of body experience and allowed him to travel to other dimensions to interact with the native beings there... he discovered these positions in a book of his own... that is all I remember.

Edit to add member-influenced memories of book:

Roughly, i read this around the age of 10, so it was about 22 years ago or so.. 1990-95? - it was in English, no memory of the cover... probably young adult reading and i do remember there were names to these poses he would do. the names of the poses had different names that were not in english, i am reminded of the martial arts poses or series of movements in karate called , "katas" ?