There is no back wall, no solid entity, no nugget of you-ness, which experience 'hits'.
Every sensation that appears solid is actually pure space. Choose a sensation, the one which seems to be most intimately associated with you and you will soon discover that there is nothing solid or tangible about it. All of your sensations are in flux and that flux is itself empty. Really, there is nothing happening.
Experience happens to no-body and the only referent is empty space.