Whenever I sit down I have like my heart beat thing in my butt
Why is that?
I would imagine it has soemthing to do with your blood circulation, maybe they way you are sitting is making it harder for the blood to get through certain veins or arteries, next time it happens, try changing your position or moving your weight around, see if that stops it.
It misses something ;PPP jk
It may be throbbing.....