I don’t know. I just googled all of these terms as I am … old. Origin of “no cap” comes from “high capping” (rap lyrics). https://amp.knowyourmeme.com/memes/no-cap-cap

Thanks !

Also : “Sus” is an abbreviation for “suspicious” often used by players of the game Among Us

af : as fuck ?

No Cap is a slang term used as an alternative to “no lie” to tell people you’re serious about something and not lying.