Answer:
water colour wash
Wet-in-wet painting
Explanation:
One tip for any watercolor wash: If you notice a mistake in a previous stroke, don’t try to fix it. Once the wash has started to dry, a new stroke will almost definitely be more noticeable than any small mistake. It’s best to leave these happy little accidents as they are.
Wet-in-wet painting is one of the most basic techniques — so basic you might have already done it before without realizing it!