USB is dissymmetric: one side is a host, the other side is a peripheral device. You can't make a peripheral device act as a host or vice versa. It is possible for a USB port to be able to act as either side; this is called USB on-the-go and is present on some mobile phones and tablets. The ports are physically device-type ports, not host-type ports. I've never seen a PC with a device port. This requires electronics on the controller, it isn't enough to make a cable that fits on both ends.
So no, you won't be able to make a PC into a USB device.
If you want to use a computer as a USB storage device, you can use a mobile phone or tablet with a USB connection instead of using a PC.
So no, you won't be able to make a PC into a USB device.
If you want to use a computer as a USB storage device, you can use a mobile phone or tablet with a USB connection instead of using a PC.