How to change Bootstrap style before it is shown?

I've been trying to manipulate the bootstrap tooltip's positioning without success.

Attempt #1:

stuff.tooltip({
    container: 'body',
    placement: function(tip, el) {
        // played with tip, but it still add style: top, left at the end...
    }
});

Attempt #2:

stuff.tooltip({
    container: 'body',
    placement: 'top'
}).on("show.bs.tooltip", function() {
    // don't have access of the tip here
});

Attempt #3:

stuff.tooltip({
    container: 'body',
    placement: 'top'
}).on("shown.bs.tooltip", function() {
    // doing anything to the tip at this point would cause visible change
});

Any ideas?