Ink Well
This is a product I designed for myself and students called the Petal Pod. It features six tiny vials you fill with ink. For color work, I use at least two different ink pigments and dip my nib alternately between each one. This gives a subtle rainbow effect and creates such a beautiful display of color on the page. It's messy!
The nib you see is called a pointed pen. There is a split down the center that when pressed, the two "tines" separate according to how much pressure you add. This pressure is applied for all downstrokes.
Nibs vary in size and flexibility and are wonderfully sensitive tools. Dipping a pen in ink causes the user to slow down when writing (drawing) and creates a rhythm to your pace. It's good for your brain, too. I literally smile when I do it.