Followbox - jQuery

index.html

<div class="follow-scroll">
  Let me follow you.
</div>

script.js

(function($) {

	var element = $(".follow-scroll"),
		  originalY = element.offset().top;

	var topMargin = 20,
		  topDistance = '';

	$(window).on('scroll', function(event) {
      var scrollTop = $(window).scrollTop();	
      var topDistance = 0;
    
      if (scrollTop < originalY){
        topDistance = 0
      }
      else{
        topDistance = scrollTop - originalY + topMargin
      }
    
	    element.stop(false, false).animate({
        top:topDistance
	    }, 500);
	});	

})(jQuery);

scripts

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>

style.css

html { box-sizing: border-box; }
*, *:before, *:after { box-sizing: inherit; }

body{
  height:2000px;
}

.follow-scroll{
background: #eee; border: 1px solid #ccc;   
  padding:20px;
  width:200px;
  text-align:center;
  position:relative;
  top:20px;
  border:1px solid tomato;
}