Honestly!! I love my ds1 very much but there is no 18 year old boy born who could make a girl shriek like that.
She is from the Meg Ryan school of sex noises but AMPLIFIED
I also can't beleive the brass neck of her - she faced us all afterwards without even a blush.
It's not the first time either, we weren't in a while back and dd (23) and ds2 (15) could hear her down stairs. Ds2 went and banked on the door and said "Do you mind, some of us are trying to revise" God Bless Him!!
I had a word with them then but it's not stopped them, they now can't be in his room with the door closed.
They don't prepare you for conversations like this at antenatal classes