JSFiddle - React, Tailwind, and code Playground
HTML
<ul class="related">
<li>Parent 1
<ul class="children">
<li>Child One</li>
<li>Child Two</li>
</ul>
</li>
<li>Parent 2
<ul class="children">
<li>Child One</li>
<li>Child Two</li>
</ul>
</li>
</ul>
CSS
.children {
display:none;
}
JavaScript
$(".related > li").click(function () {
$(this).children(".children").toggle();
});