Fling and smooth with a towel? Or just fling?
That one's for you to decide for yourself to determine which method gives you a result you're satisfied with.
I know you do tend to prefer a cut and dry "do this, then this, and then this" step by step detailed instruction, but experimenting with new techniques and how they can yield different results is part of the "fun bit" just as much as the build itself, and because of the rather unpredictable nature of the process, short of someone breaking it down to "apply .482 fluid ounces of paint to the brush, hold your wrist at a 35 degree angle, sweep upwards at a precise 47.39 degree angle at exactly 72 mm per second with a 1/4 twist exactly 2/3 of the way through the motion...etc., etc., etc." each attempt is going to come out different and yield different results. It's something you kind of have to play with a bit to figure out which range of motions and wiping/smearing technique gives you something you can stand back and say "yep, that's it right there."
But, to narrow it down a little, flinging will most likely give you streaks, small blobs, and random splatter, what you might expect from being behind a tire as it kicks up dirt and mud, or being too close when something hits the ground with a lot of impact and, well, flings crud everywhere.
On the other hand, flinging and wiping (or brushing and wiping) will give more of the result you mentioned, looking like the piece was dragged through the mud, whether crawling or getting thrown to the ground. Also note that what you use to wipe/smear the paint will also affect how it looks. A cloth will take off more paint than a paper towel, which will take off more paint than, say, a piece of crumpled up paper. How hard you wipe and whether you wipe it off or just smear it will also dramatically change how it looks.
In the end it does come back around to experimenting and finding what works best for you. It's not building a suit, but it's not staring at a screen, either. And a lot of these techniques aren't taught so much as discovered, as everyone's approach will be slightly different depending not only on available materials, but in a cast like this even the differing motions that come from different body types will factor in.