I have two dc power sources that need to work one device , how do I wire them so they short each other out?

I assume you mean so they WON'T short each other out.

One way is with diodes, but to give you any decent advice we need more info on your project.

WallyH

What is the device, what is the voltage of your DC sources and why won't one source do the trick?

you could consider your DC power supplies in a similar way as (2) 9 volt batteries....
if you connect the terminals in parallel you will get 9 volts with twice the capacity of one battery...
if you connect them in series you will get 18 volts with the capacity of one battery...
so what do you want to do?

Wallys right, Diodes could work, depending on the Loads involved. We can give better answer if we knew the 2 devices and the 2 sources of power. Thanks

How could you wire them so they "would" short out?
power supplies wired in series would increase the voltage, in parallel would increase the current.... (assuming neither is grounded of course)