6 yr olds putting pens up each others butts

[desmom19]

Late yesterday afternoon I found out that while down at a friends house 3 boys (all 6 yrs old) decided to take off their clothes and put a pen (plastic pen from a game) up each others butt.  At this point we do not know whose idea it was however according to my son they each took a turn doing it to someone.  Meanwhile the brother of one 6 yr old and sister of another 6 yr old also came in the room and it was done to them as well.  I still do not have all the details exactly however I am completely sick over this entire incident.  I had a long talk with my son regarding this but I cannot tell if he is telling the truth or not.  I was not there when it happened but was told that all the boys blamed each other as to who did it and whose idea it was etc......
At this point I don't really care and don't want to blame anyone I just want to know why on earth that they would even remotely think that this was a good idea and not wrong.  I also am concerned as to why they would even come up with something like this.  It does worry me a bit that who ever had the idea could have had some things done to them.  
These are boys that have known each other from birth.  They are BOYS (want to pee outside, use words butt, poop etc....my son has woken up in morning said mommy my pee pee muscle is hard-)
Is this something that they were just exploring.  I have yet to speak to the other mothers I have left messages for both to call me.  
I am just sick over the entire thing and not sure what to do or where to turn.

[mammo]

I agree, this could injure them.  I have to think that one has seen this or had this done to them in order for them to even do this, as it's more than experimenting.  Sounds like these boys need very close supervison at all times until you learn who is the culprit in showing them these things.

[margypops]

Well it could be dangerous apart from anything else so it doesnt sound like a good idea , it would be good to find out who got the pens ,were they shared ,not good, so you need to supervise 6 year olds more .I wouldnt call it exploring ,it sounds like a learned behavior, from the child you started it ...Find out more and be aware and watch what is happening ..speak to the other parents ..