Need some advice!

My boyfriend and I are sexually active, very sexually active. Recently(not even recently, I've been thinking about this before meeting) about asking my mother if we could go to planned parenthood and getting birth control.. 

I and my mother haven't had the greatest relationship.. we have butt heads and any sexual talks have either been put on hold or haven't been said. 

So, I'm asking my fellow ladies in any tips on asking your mother? 

Thanks!!!