If something is on the rocks it is likely to fail because of serious problems.
(Currently it looks as if the world of finance is on the rocks.)
If you are referring to an alcoholic drink it means the drink is served with ice.
(I'll have a whiskey and soda on the rocks.)
Of course this photo is of my favourite gummy bears relaxing on some rocks. But they're special rocks, they're chocolate rocks. 🙂
