Meaning:

Roughly translated as “one click, three strikes,” this term refers to a long click of the “Like” button on the Chinese streaming site Bilibili, which serves the triple function of “Like, marking as a Favorite and Tipping.” The three functions allow users to support the vloggers they follow, and are used as a criterion for Bilibili to rank the videos. As all vloggers hope their videos could reach a bigger audience, they would ask fans to give them “one click, three strikes” each time they post a new video.

Example:

A: 昨天你转发给我的视频太好笑了。

Zuótiān nǐ zhuǎnfā gěi wǒ de shìpín tài hǎoxiào le。

The video you sent me yesterday was totally hilarious.

B: 是啊，我看完后点了一键三连。

Shì a，wǒ kànwán hòu diǎn le yījiàn sānlián。

Indeed. I gave the post a long click to show my support after watching it.