Hank has been "dating" Amber for a while with her boyfriend's permission. Not that she's unhappy in her relationship, she just needs a little more sexually than he can provide. And Hank knows her boyfriend well because they are in a fantasy football league together, so he figures if she is going to spend time with another guy it might as well be a friend.
Her boyfriend told Hank she would take it anal if she were aroused enough but up until now she hadn't allowed him there. So tonight he took a lot more time with foreplay and it payed off as she didn't object when he started to finger her there. Soon he was able to slip right in and she took his whole length up inside without a problem. Soon he started filling her backside with a full load of semen and pumped as much into her as he could, staying inside her for a long time to give time to fully empty himself inside her.