This phrase was used by a friend of mine to explain her view of human nature. I have heard this view explained by various people in various guises in talk and in writing for many years, but I think this phrase captures it best.
In this view, the experience, whatever it is, whether sex, art, music or climbing Mount Everest is tantamount, and the experiencer, the person who feels these emotions and sensations, is merely a tool or an instrument for this experience to manifest itself in. There is no "substance" that can be said to exist apart from the constructed, temporary self and its flow of experiences. This can be seen as either a psychological or metaphysical doctrine, or perhaps just a convenient rule of thumb with no actual truth behind it.
As a doctrine, it has been espoused by various schools of thought, some from some kind of wisdom, and others from sheer baldheadedness. The Theravada (or "inferior") school of Buddhism believes in this. So did the Epicureans and Hedonists. Behavioral psychology could perhaps be seen as a late, practical application of this philosophy.
The opposition to this philosophy is perhaps Kant's idea that people are an end in themselves, and in scholastic philosophy, which posited the idea as soul as a substance.
From my own personal viewpoint, I have never been able to totally acept this viewpoint. Perhaps it is because for all my trying, I have not found an experience that is all consumingly orgasmically involving for me, something that I can totally sink into and forget my ego. (with the possible exception of Final Fantasy!). However, I think that in a large part, this theory fails because it is, at base, metaphysically unthinkable, if not meaningless. As I explained in relationship and independence as antinomy, the idea of a "do-er" without a "be-er" is just as meaningless as the inverse thought. People both be and do. To exist is to walk under the sun.
My metaphysics aside, if anyone out there wants to think of themselves as a disposable camera taking pictures of experiences, don't let my attitude distract you from going to raves and expereincing the dwarving power of nature