Last night I had a dream as follows:
The whole dream took place in a normal bedroom room that was lined with pink, lavender, and white striped wallpaper. The carpet was brown/pink, the bed was a twin brass bed. The desk was white. There were no windows and the light was from the ceiling(white)....Oh and im a guy and I dont have any sisters.
This was my dream, and I do not have a sister. I was talking to a young gal in her early 20's whom I had just recently learned was my half-sister(from my dad's infidelities). She was wearing nothing but a white t-shirt and striped underwear. She was petite(5'2-5"4") with brown straight hair cropped off just above the neck. Se was olive skinned and had light brown/hazel eyes, and very cute. She had asked me to tutor her for math which I gladly did because I like math. I enjoyed helping her and getting to know her. I suddenly got sleepy and went to lie down on her bed. I began to close my eyes when she came over to lay down with me. we embraced each other comfortably, very platonically. After awhile things got sexual and both of us were amazed with what we allowed ourselves to do. Then I woke up.

thanks to all who read or comment

If you don't truly have a half-sister, then I think this is a dream of self-dicovery. I would say that the half-sister, is a representation of the feminine side within you. Math's commonly seen as left brained, aka stereotypically male issues: rational, factual, abstract ... The bedroom setting tells me that this is a dream on a very personal, intimate level, and thus the reason why I consider the half-sister, being your other more feminine side. Her asking you to explain math and you explaining it represents to me the interaction and getting to know and relate these two sides of you. Your inner female is interested in this theoretical rational male part of you, and you explain it. Meanwhile the bedroom's furniture and you seeing it as "her" bed, suggests the exchange is not just one-sided... you're enveloping yourself in the world of emotions, allowing yourself to be cozy in it. The sex would be a symbolical union of your inner female with your inner male.

I tend to agree somewhat with the above reader, their are aspects of your sexuality that you are unsure of, now this does not mean that you have homosexual tendancies specifically, i see it as meaning that you wish to explore sex in greater detail as so far sex has not satisfied your inner most desires, at times you are unsure of your direction in life as well, and have often thought of going against the norm just for the shock factor this would bring about. It is time in your life to become more adventerous and find what is missing from your life.