Some clarifications:
You cannot hold the C-stick in any of the directions that would cause an Up Smash input
You don't need to release the C-stick
If you're not getting it immediately, take note of what you're getting instead:
Are you jumping? Are you up smashing? Are you down smashing? Are you dash attacking? Are you grabbing? All of these results have specific and distinct areas that the input is failing on.
Jump: You are hitting up on the control stick way too early.
Up Smash: you're inputting an up smash on the c-stick, which will NOT cause a dash attack. You could also be missing the c-stick input entirely.
Down-smash: this usually happens when you use down on the c-stick (the most common method). You're not dashing beforehand.
Dash attack: you're late on the Z-button input window.
Grab: you're late on the up control stick input. This results in a boost grab—another useful tool.
After you get consistent (I'd say 9/10 times, but whatever you're comfortable doing) with this input, try the following:
Tilted DACUS (hold left or right after the DACUS input is completed)
DACUS out of standing animation. This ensures the least amount of investment in DACUS input, equating to greatest usefulness.
DACUS out of dashdance. A solid mixup option in that you can both approach and retreat safely with DACUS.
DACUS out of downsmash. This is an essential tool because it controls multiple approach options simultaneously.
Wavedash -> DACUS. DACUS is a great launcher against floaties, and a massive combo-starter on Spacies.
Set up targets to hit with the mortar so that you learn its trajectories. This is meant to help control the stage better.
Set up a mine and try to DACUS so that you end up right next to it without detonating it. This is meant to help your spacing.
DACUS to ledge [with possible smashturn->Wavedash ledgegrab after]. This is a fantastic edgeguarding tool as the DACUS often discourages high recoveries while also covering low recoveries, and grabbing ledge after allows for invincible back airs from ledge. You can even place a mine before you WD to cover on-stage recoveries. :3 Alternatively you can swag hard on your opponent and forward air them out of the DACUS hitstun.
Something I've started doing is to get on a platform (besides Smashville/Yoshi's Island/Norfair) and DACUS from left to right while simultaneously tilting the mortar to the center of the platform. This trains multiple aspects of the tech at once, and is very time- and space-efficient, fitting nicely into pre-match handwarmers or a practice routine.
The Snake metagame is super new and super underdeveloped, especially considering how totally different PM Snake functions in regard to Brawl Snake. So while this post may seem daunting, it's meant to also encourage you to experiment with DACUS (and ALL of Snake's options) in order to find new concepts and applications. This is a character of massive untapped potential, and I'm all for encouraging every Snake main to do all that they can to help realize this potential.
