I got along well with my sister-in-law and we kept in touch, but one day she started complaining that she hadn't been satisfied with her husband (my brother) lately, and asked if we could meet up on the next day that her husband was away on a business trip. She wanted a place to release the sexual desire that had been building up, so we decided to invite my friends over and have a sex party with my sister-in-law at a hotel. My brother felt guilty, but it was for his wife's sake (lol), so we made her cum raw over and over again until she was satisfied, aiming for the most number of ejaculations she had ever had during sex.