Add ui tooltip in magento 2

Html (key classes are tooltip-toggle and tooltip-content):

<span class="my-tooltip">
    <a href="#" class="tooltip-toggle">Hover?</a>
    <span class="tooltip-content">Details here</span>
</span>

Less:

.my-tooltip {
    .lib-tooltip(right);
}

Additional details:
https://github.com/magento/magento2/blob/develop/lib/web/css/docs/tooltips.html