Press very hard and concentrate.
Form an image of yourself (suppose you had just stepped forward) on the opposite side of the wall pressing back against the wall very hard.
Press very hard and concentrate on the image pressing very hard.
(the image of pressing very hard)
Press your front surface and back surface toward each other and begin to ignore or block the thickness of the wall. (remove the wall)
Think how various parts of your body press against the wall; which parts touch and which do not.
Consider the parts of your back which press against the wall; press hard and feel how the front and back of your body press together.
Concentrate on the tension in the muscles, pain where bones meet, fleshy deformations that occur under pressure; consider body hair, perspiration, odors (smells).
This may become a very erotic exercise.