I asked 100 questions about what they were doing and where they seen it or heard about it and everyone just kept saying I don't know. I'm not sure who's idea it was or where the idea came from but I'm very concerened. I know they are not victims of abuse because they love school and the only people they are ever with are me and my 74 year old grandma. I don't want to address this in the wrong way so what should I do? I told them it was not OK to do that with anyone and if if anyone at all ever tried to touch them or get them to tough him/her to tell me right away but I'm concerned none the less. Please help. I don't know if its normal because I was an only child.

Honestly, I wouldn't worry about it too much. Kids are curious about their bodies, and simply do not have the taboos that adults do about touch and private areas. This is a great opportunity to talk to them both about what is appropriate for children and siblings, and what is not okay. (For example, kissing on the mouth is what adults do to show love, you can show love by giving hugs or kisses on the cheek.) I would continue to be vigilant about checking for signs on abuse or inappropriate behavior (as always) and to encourage them to talk to you about it, but don't panic.