Like when starting a discussion with someone on a certain topic and then talking for hours while not thinking about time or "what needs to be done" and without getting tired of the conversation. And not necessarily sticking to the topic you started but let the conversation have a free flow and allow communicating things that come to your mind.
Sometimes this could be sort of preplanned - and you try to stick at the topic at hand and try to not deviate much in order to gain some understanding or to form a closure on something particular that you need to work on (or take some kind of action in regards to) and sometimes you don't have any particular motive behind this and just feel like speaking your mind and one things leads to another and that thing leads to another one and so on and so forth... and you enjoy it.