I can relate how we did handle this, a couple of years ago, in our own situation. My daughters were then 11 & 7. They now not only continue to go to naturist swims on a regular basis, but actually encourage me to go whenever possible and also have now struck friendships at a landed naturist club nearby and implored me to join so they could attend on a regular basis. From this, I deduce that we didn't approach the subject entirely wrongly!

a) What should they tell the kids before going?

That we can swim without needing our cozzies on, so we won't have to sit around dripping and damp when we get out. That everyone else will be nude, just the same as us, so no-one will be staring. And do they want to come with us? I put the question to Pippa (7). She thought about it, asked a couple of questions and then thought it sounded cool, so came along. Her "first impressions" are at the bottom of the Soleil Bedford page. Shelley missed the first swim, but one of her main concerns before she agreed was about whether there would be other kids her age - clearly wanting peers for company.

b) Discretion about who you tell about naturism is advisable. How do they instill this into the kids without giving the wrong impression?

From memory, we pointed out that some people didn't understand naturism and would even think it was "wrong", so maybe it was the sort of thing to talk about only if anyone asked.

We had cause to go to a textile swim venue a while back. In response to my mental note, said out loud, that "We must remember to put our cozzies on" came a chuckle from one daughter and a fake sulk from the other!