My Girl[f]riend gets comfortable with my room[m]ate

My girlfriend Lauren (22/F) was hanging out at my place, drinking with me (26/M) and my roommate Sam (28/M) at the time. Lauren was(is) probably 5’2″ and 110 lbs, Filipino with a cute face but not a crowd stopper. However, she has a body that I think is just perfect, in shape with great curves for such a small woman. Since we were just staying in, and it was the summer, she was wearing just a tank top and booty shorts. I know my roommate thought she was hot, and he had a thing for asian girls, even though his girlfriend was white. Since we were long distance at the time, Lauren usually wasn’t around, so it was a treat to have her living with me for a week, and my roommate certainly did not mind. She was always friendly with him, and playful, and she knew he thought she was hot, so she would try to act really sexy around him. He was a very nice guy, and had a girlfriend, which made him the perfect target for Lauren, because she knew she could flirt heavily and he wouldn’t do anything about it.