Well I never play the actuall base guitar, but you can get a petal for your electric (Or hybrid) that drops your guitar an octive. A bass is two octives down. And in that sense,  you're pretty close. And then just riff like you would normally. Try out some rhythms.

I play the piano, and if you're just looking to support your guitar work and not really learn the instrument indepth you can figure out chords (Root third fifth-> major) (root fifth octive -> standard barrechord minor). Then you can comp with that level of knowledge.