Always Show Tooltip ( Angular Material2)

I have somebuttons

            <button mdTooltip="bye" mdTooltipPosition="left" md-mini-fab>
                BYE
            </button>
            <button mdTooltip="hi" mdTooltipPosition="left" md-mini-fab>
                HI
            </button>

The tooltips show on "hover" by default. Is there a way to make it always show? (Show on page load and stay)