In uncontrolled, spotty, inconsistent sections around the clock! Hah, no, usually my drawing work gets done from around 5 am to noon. Then I paint and experiment with stuff in the late afternoon and cool down with sketches/indulgent drawing the rest of the evening.
Schedules are so important to set up for yourself and once I graduated, I found it easy to just adapt it around the previous schedule I had in art school. Keeps the mojo flowin', yo!