Trust me even the most expensive of beds get squeeky after some good love making ..lol.
But yeah I guess it is ackward if you are used to live alone and then your parents vist you or you go vist them. How about you hearing your parents....what you do in such situation???
A very easy solution. It'll cost u exactly a 100 Quid.
Buy an Ipod.
Stick the headphones to ur ears... sleep tight.