Well the hiding, karaing or whatever you want to call it and it’s easiest execution depends on the situation.
For doing an anti-air ultra it’s very easy to keep the joystick down/back then press mk+lp twice (somehow easier for me than mk+lp,lp), then slide with the joystick from down/back to just back (or back/up) and press lk + hp. This is not just for hiding your jabs but lowering your hit box during the medium kick. With this easy and really fast doable motion you’ll find yourself with their leg or arm inside your body (you’re invincible at this point) when your ultra demon starts a lot.
This method can also be used for people doing focus baiting from sweep range too much. In this case do hk+jab twice instead of mk+lp. I must admit, suck at that though. My old age starts to show i guess
When being close to the opponent where any attack would hit him before the demon, i suggest pressing forward and keep it pressed and do lp+mp twice (so it would do the overhead) then press back and lk+hp. All this rapid enough to make the demon come out before the overhead starts hitting the other player.
When doing a super demon, in the middle of a block string or just walk up super i also use the overhead cancel a lot with the following input. Forward (and keep it pressed) mp+lp then slide with the joystick from forward to down/foward and press lk+hp. Because with the super all directions (for demon and overhead) are forward, it’s even easier than doing an overhead into ultra demon where you have to change direction to back.
Of course this is my personal preference, which works best for me. Some people do better with other variations. Maybe those tips from someone with not a so good execution help you more than from a pro who can do any input method without problems anyway.