I made some almond bark, and had a small amount of white chocolate morsels left over from something else. I melted it in a double boiler, and I wanted to drizzle it on the bark, but it never reached a 'drizzly' consistency. It melted, but the bottom part seemed to be more solid. It's too late for this batch, as I ruined it completely trying to thin it. Do I need to add something to it? (I did add a tiny bit of oil.) Was it too hot? What should I do next time?