Affecting Fullcalendar today button .fc-today-button

I'm having trouble getting custom controls to work when clicking the 'today' button that is part of Fullcalendar.

All the documentation I can find tells me that Fullcalendar's built-in controls can be affected using two methods:

So, this one works for me when it's applied to previous, next, month, agendaWeek and agendaDay, but not for 'today' (button.fc-today-button):

    $('body').on('click', 'button.fc-next-button', function() {
            console.log('I Clicked Next');
    });

Some documentation also say that this works, although I can't make it do so on any button:

    $('.fc-next-button span').click(function(){
            console.log('I Clicked Next');
    });

Does anyone know why this is and what I'm doing wrong?