Yes, it is not so easy to turn on the laughing gas but when it is turned on, it stays turned on. I am not sure if it is solely about Fe. I know some delta STs who have this similar trait. So I think it is not about Fe valuing, maybe it is about low Fe or Fx.

I think when people genuinely start to laugh, they keep on laughing. I think that's why there are funny video compilations, even if you don't laugh for a while, after watching the video for a while, you start to laugh and then keep on laughing, not because those parts are more funny but because the laughing gas is turned on. I think it is a human trait. However, strong F types may have better control over the button of their laughing gas.

Yet again, ofcourse some types can find their laughing gas turned on more frequently than others and/or some types would be more willingly to turn it on.