SaraBee – It is good to hear from you again.
In a long life of observing myself, and experiencing a lot of pain and a lot of laughs about sex, I see that occasional sexual release is vital – as you say, ‘important for our survival’.
What avoidance does is quite subtle, but very powerful. If handled with awareness it can be a way to pierce higher levels of awareness – but if not it can lead to neurosis. Think of Freud! So your dream was right in its warning.
The business with your younger sister is easily explainable. Considering that a dream image is a paste up of your feelings, and that you probably have subtle blockages about sex at the moment, it seems likely that it was the safest option to use your sister as a means of bringing balance to you – in other words avoiding neurotic symptoms.
You say that neither of our libidos are firing. Wrong; otherwise you would not have these dreams. One of the main functions of dreams are to bring the system of mind and body back to balance –self regulation. Sexual drive is largely physical. After all as far as our brain is concerned we are two thirds animal. The brain is split into three sections – the reptile brain, the mammalian brain and the human brain; and that is not counting the cellular brain or spinal brain. So we are only a quarter human. We sit on top of a long and ancient past. That is why there is so many breakdowns in our society – we fail to understand what we are and do not take care of our animal self. See
http://dreamhawk.com/dream-encyclopedia/brain-levels-and-dreams/You have in fact spelt out this situation perfectly for me in saying, “whilst when I was in the dream it felt comforting, in my waking life I've no interest and feel rather perturbed!!”
And there is the conflict between your whole self expressed in dreams, and the quarter self that you are aware of. So take it easy.
Tony