Something like the following is the best you can hope for.
- Easily share access to USB devices between two computers
- LED lights indicate which computer has access
- Gain instant access to your USB devices by plugging one USB cable into your computer
- Simply press a button to switch individual USB devices from one computer to another
- Both computers have direct access to the printer thanks to Automatic Printer Sharing
- Plug and play set up and easy to use with no network required
Since we don't really do product suggestions here at Superuser here is a single Example of the device described. There are others that'll work similarly to this single example. You will be unable to share a USB device with multiple computers at the same time.
Serial devices that came before
Universal Serial Bus devices. USB devices are not designed to be accessed by multiple hosts at the sametime. Its the same reason you cannot share a USB device with a VMWare Guest Operating System and the Host System at the sametime and have to disconnect/connect the device.