This dream may symbolize a desire for a closer and more intimate relationship with your sister. The fact that she is described as a 30-year-old woman with specific physical features suggests that she represents a mature and sexually attractive figure in your life. The act of oral sex can also be seen as a metaphor for communication and a desire for a deeper connection with your sister. The fact that she is smiling and seems happy in the dream may indicate that this is a positive and fulfilling experience for both of you. The focus on the testicles may symbolize a need for emotional nurturing and care in your relationship with your sister. The act of ejaculation on her tongue may represent a release of pent-up emotions or desires. Overall, this dream may be a reflection of your subconscious desires for a closer and more intimate bond with your sister.