Drawing at the zoo today, using a technique James Gurney demoed at Spectrum. I’m thinking it may turn into a favorite method of mine, because it’s easy to carry around and lets you block in values extremely quickly.
Essentially, just get 2 watercolor pens (the ones that you can fill up with whatever) and fill one with water, and the other with an ink/water solution (the proportion can vary) which you inject into the pen with a syringe. You can use them like a normal brush pen (or brush and ink setup), but then also easily lay in washes.
It’s a great, portable setup.