So ive been playing a lil of fagat and for some reason i cant do double hadouken. Its wierd because i have no problem doing genocide, (arrows or analog stick on a PS3), but for some reason whenever i try to use the analog stick, it either
This is analog stick for destruction sorry, i can do genocide 
knee->genocide is probably something really awkward like:
d df f d df (press K here) (press the other kicks shortly after) f (release KKK after knee hits for super cancal)
wait longer before you press the kicks, you’re not going far enough up before you press them.
actually i can do it if i pretend the analog stick is a fightstick, but obviously thats not possible in a real fight cause id be holding it wierd
its mainly the first that is a problem, it just keeps doing ex knee
After the first qcf motion, you’re probably not going back into neutral properly for the 2nd qcf. Go into training mode, turn on the inputs and see what’s wrong.
You have way more time than you think you do to perform an ultra. Chill out, do it slowly. Eventually you’ll naturally speed it up, but it really doesn’t require super fast motions.
EX knee means you’re hitting the buttons too early. Knee > Genocide means you’re mashing.
Check out the sticky on execution. It has advice on how to help you figure out what you’re doing wrong and fix it.