CraftLawrence,
так?
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
body {
height: 2000px;
}
.air_call {
z-index: 5;
display: block;
width: 65px;
height: 65px;
position: fixed;
border-radius: 50%;
transition: .5s;
background: #61a7a1 url(/img/call.png) center center no-repeat;
background-size: 80%;
right: 55px;
bottom: 250px;
transition: all 1s ease-in;
}
.to{
right: 0px;
bottom: 0px;
}
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(function() {
$(window).scroll(function(){
$( ".air_call" ).toggleClass('to',$(this).scrollTop() > 10)
});
});
</script>
</head>
<body>
<header>
<a href="#" class="air_call"></a>
</header>
</body>
</html>