Your girlfriend Emma walks in on you and Susan

Susan is a real pro cock-sucker. Most girls struggle with your size at first, so you think she must have sucked some big cocks in the past. You know she's dated some black guys so you figure that was probably it.

You love watching Susan's mouth expand as she takes in your fat cock. You're sliding in and out quickly and you can feel yourself approaching climax when all of a sudden the door opens and Emma appears in the doorway.