<div class="element">
  
</div>

.element:after{
content: "";
display: inline-block;
animation: buttonEmoji 2s infinite;
  width: 200px;
  height: 200px;
  background: red;
}

@keyframes buttonEmoji {
    0% {
        transform: rotate(0deg);
    }
    10% {
        transform: rotate(8deg);
    }
    15% {
        transform: rotate(-8deg);
    }
    20% {
        transform: rotate(8deg);
    }
    25% {
        transform: rotate(-8deg);
    }
    30% {
        transform: rotate(8deg);
    }
    35% {
        transform: rotate(-8deg);
    }
    40% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(0deg);
    }
}