Let us be clear: there's nothing wrong with having sex.
Provided you are safe, responsible, mature and, ideally, in love... have at it, people.
But some neighbors of yours are here to tell you to keep it down a bit. Please. There could be kids around. We may need to tell them you're beating your girlfriend instead of making sweet love to her.
(No, really, that's what one of the following authors actually told his son.)
So protect yourself, consider the following advice and, seriously, buy a new bed frame already...