Since the sewing machine I got for Christmas last year is still in the box, unopened, a crochet steek was clearly the choice.
I am no great crochet wizard, but a crocheted steek really requires no previous crochet experience, just a hook and some yarn. Push the hook under 1 leg of each stitch you want to join, wrap the yarn and pull it through--it's not much harder than that.
The lines of crochet stitches ensure that your yarn won't unravel when you cut through the middle stitch. I did a swatch in the round for this sweater, and intended to practice steeking on it, but . . . I couldn't find it. So, I just went right ahead with the sweater--if I ever do find the swatch, I can use it for a tutorial!
Snip snip! You can see the lines of crochet holding the knit stitches tightly--no unraveling here. The only places I had some trouble with unraveling were the top and bottom of the steek--not being an expert, I don't know the best way to handle this issue, I just used the ends of the crochet yarn to catch a few floats and stitches and tie them all together. The two loose edges from the steek fold back behind the collar, so you'll never see the mess.
And voila! A big gaping hole in my sweater. It just needs a collar.