I've tried sidechaining before - is that what you mean with getting the kick to sit inside the bass? This usually creates a pretty unsubtle pumping effect, which is nice but very noticeable, and not what I hear other people doing.

I've even tried splitting the bassline in two using filters, then sidechaining the kick to the low frequency part, but not without much success. And I get the feeling I'm stabbing about in the dark not quite knowing what I am trying to achieve with all these shennanigans.

Oh, for a comprehensive book that explains all these things.