Freaking out a little - how do I fix this?

[Marley&Me]

I have no experience either but, is it possible you could bring it up with his mother? And maybe she could ask L what that was all about.

[Starfish]

I'm not sure that kids that age even know what sex is, so it may just be a word that your DD or L are using without actually knowing what it means. I remember when my sister and I were little we thought that "sex" was kissing someone in a car or a bed. (Really ) If you're worried, maybe talk to L's mother, but chances are it could be something completely innocent.