Mive embarrment.What should I do ?

Me and my friends were talking on my trampoline, we were going on about wonderbras and a problem page about someone who had nipple discharge ( i know its childish!! ) we talked about a woman who used her as a table then we heard i noise like someone running off and sing. It was someone on the other side of the hedge from school who'd heard it all. It the holidays now but i am so sure he is going to tell everyone, :( please help i am mortified