First thing to do is install the Compatibility Skeleton. Most mods dealing with animations will need it anyway, so regardless of your mod preferences, you should have it always installed by default. You can find it here at the Nexus.
Once that's installed, it's time to choose bouncy animations for your ladies. There exist 2 sets of animations as far as I can tell: Thaumx's Classic BNB and the more modern and in my opinion FAR more natural and superior Visualcore's Frozen Feminine Animations. Go on those two mod pages and check the images and videos available. Install either (not both) according to their instructions (if you need assistance with that feel free to comment here) and proceed with the next step.
Choose and install a body replacer compatible with BNB animations. There's tons of options here at the Nexus. Some of the best are Junkacc11's Type 4 body, Dimon99's Type 3 body, Necroscope's Type 6, and my own Cali Pin-Up Type body included as an optional download in my Desert Fox mod page. Choose one of those and install according to their instructions.
Install each mod IN THAT SPECIFFIC ORDER, letting the latters win file conflicts on your mod manager, or manually overwriting everything in each case.
You can also use any animation set from Oblivion. There are two that I use. Woman's Walk and NoMaam Breathing Idles. IMHO, the Woman's Walk is the sexiest available. The Breathing Idles adds bounce when the NPC is, well, standing idle.
How to properly install and use Bouncing Natural Breasts. (2 comments)
Install each mod IN THAT SPECIFFIC ORDER, letting the latters win file conflicts on your mod manager, or manually overwriting everything in each case.
IMHO, the Woman's Walk is the sexiest available. The Breathing Idles adds bounce when the NPC is, well, standing idle.