``Which do you like more, my sister or me?'' My girlfriend and I promise to get married and go back and forth in each other's rooms. I thought those happy days would last forever...until that day. As soon as my girlfriend left her house on a business trip, I was actively seduced by her sister, and while I felt guilty, I realized that my girlfriend's sister was more erotic and cuter than her, and that her sperm was coming from her sister. I fucked her until I ran out. Sex pickled with my sister