You are no fun

The origin of this phrase "you got no jams" comes from korean word "재미 (jaemi)" which means "fun". Jaemi and jams sound familiar, so Rap Monster put jams instead of Jaemi in the sentence making it funnier.

P.S : In korean, "you got no jams" is "너 재미없어 (neo jaemi obseo)"

when you got that sauce that's lookin extra fire.

A very terrible insult. If you have no jams, on a scale of Jimin to Namjoon, you are Jimin.

It’s an inside BTS joke made by RM and Jimin.

That means that someone is not funny. As you know you can also use it in your Real life cause why not actually.

U have become a jamless person in life.

The highest level of insult possible.
Literally meaning you have no fun. You are a lifeless peice o' shit.

If someone says this to you, don't take it as an insult. Think of it this way, a cute, priceless baby that we musthink protecthe at all costs was told the same thing. Consider yourself lucky!!