At A Loss

I had friends over today for a get together. The kids (ages 5-7) were all in my bedroom towards the end of the night.

My friends went to look for them and found my little one (aged 5) and the older boy (aged 6) in the bathroom - the boy was fully nude and my little one was fully nude from the waist down.

OMG!! They yelled at them, got them dressed and sent them out (and no more closed doors for sure) but now what?? I talked to the little one for a bit but how do I handle it?

We'll talk more to them tomorrow - to both of mine because the older one (aged 7) should have never let the little one go in to the bathroom with the boy.

Should I be super concerned? Is this normal? I feel so embarrassed, upset, at a loss?!?!?!

I need advice.