Listening to teens is like listening to another version of English. The words are recognizable, but not the meaning. BUT!! They are not quite as cool as they think.
Take for example the ubiquitous "O.M.G." Young people think they own it, but its first recognized in print use was Sept. 1917. Lord John Arbuthnot Fisher wrote it in a letter to Winston Churchill, railing against Churchill's handling of Gallipoli. So there. Now some "cool" bidding.
It's gone "Pass, Pass, Pass" and now it's up to you. Let's talk concept then we'll give you a "rule" (which we consider a "suggestions" rather than a rule...)
When it's been three passes to you, the points are going to be fairly balanced around the table. Third hand, to your right, is probably light, since third hand tries like the devil to find a bid. You are like the little Dutch boy with his thumb in the dike, and when you bid, the dam opens. Whoever owns the Spades is likely to win the partscore.
SO!! To open in 4th seat, you need either a reasonably sound opener, or control of the Spades (either to bid them or to give the opponents a very unpleasant trump split). Thus is born "The Rule of 15". Here's how it works: You add the high card points in your hand plus the number of Spades you hold. If it hits 15, open. Otherwise, let it go and pass. The score of "0" is better than a minus.
Let's try this and see how it works.