Tail presses on tilted slopes
so i've been trying to get into buttering, and i've managed to hold successful tail presses on the bunny slopes. I went on a normal green run yesterday to try it out (beginner's slope had a ridiculously long lift line and was chock full of toddlers and skischool people), however, and had difficulties holding a straight press - i would turn abruptly onto my toe or heelside sometimes.
After a while, I realized that part of the reason why I couldn't hold the press was because some parts of the slope was tilted (ie the left side is lower than the right side, for example). If i tried pressing down a tilted slope I would end up on one edge and turn abruptly.
My question is - is it at all possible to press (and butter in general) on slopes that aren't totally flat? Would it be possible to steer and have more control after more practice, or are these considered "flatland" tricks for a reason?