<div class="mouth1"></div>
<div class="mouth2"></div>
.mouth1 {
background-color: #fff;
position: absolute;
left: 100px;
top: 155px;
width: 200px;
height: 200px;
border-radius: 100px;
z-index: 1;
}
.mouth2 {
background-color: #C4CD14;
position: absolute;
left: 50px;
top: 30px;
width: 300px;
height: 300px;
border-radius: 150px;
z-index: 2;
}