My 10 year old son recently played "truth or dare" with his 7 year old sister. They touched each other's private areas, and she kissed his genitals briefly before they both grew uncomfortable and stopped. This is the only occasion on which this has happened. My son has also been diagnosed with ADHD. I've been looking on "normal childhood sexual behaviors" and I can't decide if this could be classified as normal. They both say it was consensual, and there has been no history of bullying.