We're coworkers on the train together after a corporate happy hour. On the train ride back we end up flirting and I fairly aggressive grope you! I eventually get to your cock which, just as I’d hoped, is rock hard. This is the sign I was looking for and take it as encouragement to get off at your stop. You only realize something is up when I invite myself into your apartment (in spite of you knowing I have a girlfriend). From there, I have my way with you!