[QUESTION] What is this Guitar technique called?

Hello everyone,

I see this technique people play quite often in rock music. They usually use it in between parts. What it looks like to me is holding a 3-4 string bar chord playing and sliding it. You get a grinding electric sound. The problem is when I try to imitate it, it doesn’t sound bold and clear at all. Just sounds dirty and hardly noticeable. So I decided to look in to it but could not find what it is called or info about how to do it properly. Here is an example its someone covering cherub rock solo and in between parts he does it here and there:

https://www.youtube.com/watch?v=E250opxjO04

Can you tell me what it is called? And how to do it so it sounds right?