So, I main Balrog and I don't intend on actually using the Dirty Bull pretty much ever, no matter what thxyoutoo thinks.
 
BUT... going through the trials, I need to be able to execute it but can't seem to do anything besides jump backwards. What am I missing here? Clearly I'm doing something wrong, but I don't know what it is. I'm sure it's something obvious and I'll feel like an idiot, but whatever. Can anyone help? Thanks!

Do an empty jump and spin the stick like crazy. As soon as you touchdown, mash the three punches.

you gotta buffer those. jumping into them is the most common tactic. some people jab while buffering. others can just do it. 

 look it up on youtube im sure theres plenty of goodstuff

Dash forward and use that to buffer the double spin. Or jump, if you're like that.

Yup, jumping into a dude definitely works.  Some inputs from my experience don't really require you to be stationary (standing still, crouching, etc.) so inputting anything while in mid-air then mashing whatever buttons you need to mash once you land will work fine.

Jump in, do the first circle in the air

buffer it while doing something else, (Jumping, dashing forward, etc), With the way rog's punches sometimes whiff the opponent, that''s the perfect time to start churning as all the time before one would think he's open for an attack.