“Bug” is a nickname for a semi-automatic mechanical key. Dots are made automatically by the device, often with a pendulum bouncing a movable contact against a fixed one as long as the lever is held. Dashes are made by hand. Electronic keyers make both dots and dashes automatically, but many of them allow for a “bug mode” or can be set up as “e-bugs.” So look for that terminology– bug mode or e-bug– in your keyer manual, and if you can turn it on your paddle will work just like a bug. But if your keyer doesn’t offer that feature, don’t despair– there’s more than one way to skin this particular cat.
Keeping in mind with a bug or with a paddle used as a bug, dashes are made by hand rather than automatically. So the dash paddle is effectively the same as a straight key, and guess what– the entire purpose of your electronic keyer is to perform like a straight key! So all you need to do is bypass the keyer with the dash line, and connect it in parallel with the keyer. The net effect is that the keyer works with the dot lever only, and the dash lever is connected to the output of the keyer and works in parallel like a straight key. In other words, an e-bug.