Does a Cat Purr Soundtrack Exist?

So Brian and I are starting to get worried that the only way these babies are going to be able to sleep following there birth is with some sort of purring cat noise. Our cat Popcorn has always been a lap cat but now if I lay down he is quick to join me. I have worked hard to teach him that he is not allowed to actually walk on the belly but that doesn't stop him from doing the scoot up as far as he can...