Please sit well. OK, I sit well.

请坐好。好的，我坐好。

Sit well back in your chair.

靠在椅背上，放松些。

Of course. Everybody, please sit well.

那当然了。大家都坐好了。

I would sit well.

我就立刻坐好了。

If these phrases don't sit well, that's the point.

这些说法是不是听起来很怪，对，这就是重点。