When I was describing poly to some coworkers, one of them said "Oh, you're swingers." I replied "No, that's polyfuckery. Polyamory is about loving relationships, we want more than sex." It was like a light clicked on in her head at that.
I think attaching the "poly" to "fuck" to illustrate swinging and then pointing out polyamory is "many loves" helps a lot of folks to understand it.
And I never assume it's a bad thing when they say they don't think they could do it. It's a foreign concept to them and they really don't think they could do it because they have no idea how to go about doing it.