If you dreamed that you had sexual intercourse with your older sister: An outsider may cause sadness in the matters you want to achieve, you should concentrate on your plans and wishes and make efforts in this direction, dear Pisces. To see that you have sexual intercourse with your sister in your dream refers to helping each other in the family, achieving good works by using your mind, enjoying life, ending your problems, and smiling. To see that you have sexual intercourse with your sister in your dream and to be sad indicates that you will stay away from the things you will regret and be happy.