system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do actors cry on command?
gpt
Professionally trained actor here. 

So, there are several ways of doing this. There are physical ways, some people have things they can do to their body to induce tears, like pinching a nerve or the such. But most actors who need to generate tears do so through emotional memory. We think very intensely about a memory when we were sad, concentrating on that memory and bringing it to the present. If done intensely enough, it can reliably bring you to tears.