https://www.twitch.tv/spiderweb__/clip/PlausibleSpineyClipsmomNotATK

When jumping from moving platform it will prevent screen scrolling until you hit the ground, thus allowing you to get the bone quickly without waiting for another cycle from the 2nd platform. This bone is still possible to get with a very precise jump but this method is pretty much guaranteed to work. Depending on how you get hit from the bat (it's also possible to not get hit if lucky) you may be able to just walk onto the first platform rather than jump on it.

*Link updated