As you said, sounds like the tail is not getting enough pressure mid to end of the turn and the nose is plowing into the end of the turn. Perhaps you are just rotating too deeply and driving your hip late in the turn. Some drills you could try in order to even out pressure if not increase tail pressure are:
Try and hopping off of the tail, sort of an ollie, exiting the turn, start with skidded turns and try to progress to full carve.
Try to grap the toe edge of your board behind your rear foot with your rear hand on heel sides. Lead hand to heel edge in front of your lead heel on toe sides. Again start slow and skidded, maybe even visualize and practice stationary prior to try it moving. There should be lots of knee bend with this one, some waist but, again start slow and skidded.
Ride ride with arms crossed across chest. This will feel completely strange as it will really take you out of your comfort zone, take er' slow at first.
Practice short radius turns keeping upperbody static, use hips, knees and legs to initate and complete turns. Often helps to visually pick a downhill point to focus on. Progressively work towards fully carved turns.
There are a few more drills and weighting/unweighting positioning discussions on the board here. Dan Bogardus did one I think titled "Your butt and where it should be" that was pretty good and seems aplicable.