4 year old obsession with his private parts

[Camilla10]

Hi Ladies
Please help....
I'm am so shocked to hear that yesterday my 4yo son was at a playdate and the mum of the house went upstairs to find her son naked from the waist down in bed and my son acting coy around him. When she asked what they had been up to her son said my son was trying to stick his willy into his bottom. I am devasted, he has never been exposed to anything sexual obviously and the only thing I can think is that he is being influenced by the bigger boys in the playground at school (he just started reception in Sept 09). Has anyone ever experienced this sort of behaviour ad if so how do I play it?
I appreciate anyones help.
thank you

Relax. This is very normal. A bum has a hole. A willy might fit? So might a brick, a carrot, a bit of playdough?

Discovering their bodies and exploration amongst friends is totally normal and not a sign of 'exposure' or anything untoward at all. They do it with their friends because we never talk about it...maybe time to start?

Also, your son is likely to go through several phases with his willy and you're now just starting the tip of the iceberg, so get ready

my mum once caught my niece and her friend (at about the same age) trying to stick pencils up their bum. They thought it was hilarious, not so my mother!