All Se egos can be relatively lazy, but when they need to act for whatever reason, that's the last thing you'd even think of calling them.

For me, as an irrational Se ego, I'm basically low activity, and then I spring into action when I feel I need to. Actually, something I've noticed about myself is that I'm more relaxed when I'm doing something than when I'm traditionally "chilling" e.g. I'd rather be in the heat of battle than sat thinking through a philosophical problem - said sitting makes me restless and something anxious, whereas activity calms me down.

As for LSIs, I guess they follow a similar way of life, except that they're less prone to sudden bouts of energy or whatever.