I drew this little paint tube with my calligraphy pen. Koosje Koene had mentioned drawing with a water-soluble fineliner. I don't have one of those. But I remembered that the ink in my calligraphy pen was water-soluble. Did I tell you I'm in a "use-what-you-have-rather-than-buy-more-art-supplies" phase?
Once the drawing was finished (5 minutes max), I used a damp paintbrush to spread the ink to create volume and reflections (2 minutes?). Who says they don't have time to draw every day?