So "LMK" -- let me know -- and "WYCM" -- will you call me? -- are innocent enough.
But the issue, especially for parents, is understanding the slang that could signal some dangerous teen behavior, such as "GNOC,'" which means "get naked on camera."
And it certainly helps for a parent to know that "PIR" means parent in room, which could mean the teen wants to have a conversation about things that his or her mom and dad might not approve of.