I used to conveniently disappear whenever a watermelon would roll into the kitchen. Eat it? I sure would. But slice it? Not if I wanted to avoid a trip to the emergency room.
Watermelons are big, bulky, and, erm, bulbous, with a propensity to tumble right off your cutting board. There have been countless times when I've lost the entire blade of my knife to the melon, Sword in the Stone-style, and have had to call in reinforcements to rescue me it.
But the more I approached watermelon prep methodically, stealing smart steps from segmenting oranges and breaking down pineapples, the less I feared for my digits.
First, create a flat surface to avoid the Wobble Problem™: Slice the cap off the top and bottom of the melon so that it can stand up on your cutting board, straight and stable. (Talk about good posture.)
If you're making cubes or slabs, follow the curve of the melon with a sharp knife, removing the skin as if you were segmenting an orange or denuding a pineapple.
Now that you've got a bald melon, you won't have to wrestle with that tough skin. Cut it down the center, then turn the halves onto their flat sides and cut those into thick slabs, which can then be cross-hatched into squares, rectangles, triangles, or even diamonds (rhombuses might be challenging...).
Or, if you want wedges with the rind still on, skip that step: Instead, slice down the center of the watermelon, top to bottom, while the skin is still on. (It'll still be easier now that you have a flat, soft point of entry at the top.) You'll be left with two flat halves that you can lie face side down on the board and slice into half-moons or wedges.
It's fast, easy, and safe. You'll get consistent-sized pieces, if you care about that sort of thing, and you'll have zero reason to avoid slicing watermelon or to not make any of these refreshing, summer-shrieking recipes:
A (former) student of English, a lover of raisins, a user of comma splices. My spirit animal is an eggplant. I'm probably the person who picked all of the cookie dough out of the cookie dough ice cream. For that, I'm sorry.