mrrm mrrm

A friendly noise, made to express happiness, agreement, acknowledgment, and so on.

It can also just be used as a random reaction noise when you don’t know what to say.

Mostly found on the internet. Though I have to say, using it in irl spaces makes you very cringe

Toby: Hey, I’m getting testosterone tomorrow!!!
Justin: Yo, I’m so happy for you, bro!
Toby: mrrm mrrm

Or

Mike: look at this funny meme!
*meme*
Julie: mrrm mrrm