Max in your mother's room.

Sometime when guys gets a little excited, they, you know, have some orgasms. Max on the other hand has this in multiple occations.

Where can I find Max jizz?

If you're in a Skype call, and Max is playing a video game, he will make his beautiful jizz sound.

In your mother's room.

Many people find this sound very funny, and then a meme (?) was born.