Thinned chocolate should be fluid but not watery. If you lift your spoon, it should fall in a steady ribbon and pile on itself before melting back into the bowl. If it runs off like a scared squirrel, you added too much oil. Add a few more chocolate chips to thicken it back up.
For extra fun, stir in a splash of vanilla extract or a tiny bit of instant coffee powder. It won’t make it taste like coffee—it just makes the chocolate taste more like itself. Chocolate inception. You’re welcome.