In a highly competitive, high-level auction, where RHO has just made an apparent sacrifice bid, you can agree that a pass by you shows some kind of in-between hand where you’re not sure whether it’s better to bid one more or to double. Partner can then use that information at their turn to bid one more or to double.
If my own experience is any guide, 9 times out of 10 after you’ve made a forcing pass partner will tank for several agonizing seconds and then pass.
The other 1 time out of 10, partner will pass without tanking.