In order to help you understand push media, defining the opposite, pull media, seems to be a good thing. Pull media is when you must perform a pulling action in order to experience the media's full capacity. A radio device is a good example of pull media; for the radio device to function, you must pull out (extend) the antenna.
		Push media, logically, needs to be pushed (inserted) into something in order to function. This can be clearly illustrated with a floppy disk.
		Knowing this, the difference between push and pull media should be very clear. Pull media recieves (reads) contents from what is surrounding it, while push media's contents is transferred to its surroundings, eg. a floppy disk in a floppy disk drive (reader).