Sexuality in 6 year old boy

[NanErika]

My 6-year old son is a gentle, sweet intelligent little person. He has sucked his fingers for comfort since infancy. and also likes to stroke his face with his blanket when he is tired or thoughtful. He loves to be held and stroked. I am always happy to cuddle and kiss him but a situation arose last night with which I was not entirely comfortable. Whilst reading to him I found he had taken my hand and was gently stroking his nipples with it while he listened. I discreetly moved my hand to his arm and stroked that, but he moved my hand back. I tried to take my hand away but he asked me to keep stroking ?because it feels nice?. I was not entirely comfortable with this but didn?t know how to tell him without drawing attention to it.
I am obviously pleased that he is a sensual person and is becoming aware of his body. However, his body is his own, and at this age it is private ? I don?t touch him intimately except to help him wash and dress, and as he is fully toilet trained now I don?t need to clean him there anymore either. I would always emphasise to him that he can show or tell me about anything that hurts or about which he is concerned or has a question, but how can I let him know that it is not appropriate for me to touch him in certain places, even if it feel s good to him, without making him feel that his body is dirty or in some way not nice that I do not want to touch it? Obviously little boys are always fiddling with their willies, but how can I let him know that it is best to do this in private? He also says things like ?my willy feels nice when you push me on the swing? or ?go faster over that hill as it makes my willy tickle?. I am not too sure what to say when he says this ? I know it is normal and there is nothing wrong with it, and I want to avoid making him feel as though he is dirty or strange for these feelings. How do I approach these situations?