Here is flush button.

这是冲水按钮。

youdao

Now when I have finished pooping , I just need to push the flush button.

现在当我大完便后，我只需要按一下冲洗按钮。

youdao

He had slept little, but the knot of his red tie was predictably flush against the top button.

WSJ: Jason Gay: The Heart of a Giant Win

The volume rocker is on the opposite side and the power button sits nearly flush with the tablet's frame on the upper-left corner.

ENGADGET: Lenovo IdeaTab S2110 review: a competent Transformer competitor running Android 4.0

It's a little better than the design method used on the Droid DNA, where the power button is completely flush and quite difficult to press, though the buttons here still gave us trouble from time to time.

ENGADGET: HTC One VX review: AT&T's latest mid-range smartphone is worth a closer look