Pass additional arguments to event handler?

i have my functions defined in an object like this:

_clickHandler: function(event){
  event.preventDefault();

},

attachClickEv: function(element){
  ......
  element.on('click', this._clickHandler);
},

the problem is that I cannot seem to pass "this" to the clickHandler function

I know that I could wrap that in another function like

var tthis = this;
element.on('click', function(event){
  tthis._clickHandler(event, tthis);
});

but then I cannot unhook the function later with

element.off('click', this._clickHandler);

is there any other way to do it?