Seeking this kind of beautiful novel

The protagonist traveled to the ancient world and returned to the original world soon after. However, there was a small tail (attack or receive) behind him. Then, he began to teach skills or receive skills to survive in this world.
The previous content was not important. The most important thing was that there had to be a backhanded joke ~

Answer 1

I didn't know what the 'clock stem' meant. If you can provide more background information or context, I will try my best to provide you with a more accurate answer.