When I was five, I was the flower-girl in my aunt's wedding. I got to toss confetti from a basket that was about twice as full as it needed to be. I was told to toss one handful to the left and one to the right, until I got to the stage.
What they didn't count on was a traffic jam.
I tossed like a pro. Left, right, left, right. And when the line stopped mid-way down the aisle, I kept tossing. Left, right, left, right, as confetti piled up around my feet. I ran out long before the bridesmaids all made it up on stage. Never ask 6 ladies to quickly climb stairs in long, tight column gowns.
That's how markers work too. You don't have to go anywhere for them to release ink. With colored pencil, you have to physically drag and press to make a mark. No movement, no mark.
Not markers. They gush as soon as you touch down and keep gushing until you lift up.
That feature works against people with hesitant strokes.
See the ink pools on either end of this orange stroke? That's a 1 second stop in my movement. One second is enough to put little blobs on the beginning or end of any stroke you make.
Smooth blending is the result of an even layer of color and an even dry time. Concentrations or pools are difficult to blend because they require more attention and then stay wet longer than surrounding areas.
Hesitation blobs are especially problematic when you leave one in the middle of a face or in an area of what should be smooth sky or background.
A smooth stroke will touch down, move, and lift in one smooth stroke. It's evenly timed and balanced, without leaving a beginning or end blob.