My son was still pretty chunky on his second Halloween, and while he was walking around in his diaper one day the idea of a sumo wrestler came to me. I couldn't just put him in a diaper and let him run around outside in October, though; he'd be cold, and that would just be too easy besides. So began about a three month long project. I took a long sleeved onesie from his closet, found an off-white long sleeved onesie with a turtleneck (one size larger to allow room for stuffing) and dyed it beige, and sewed the two together at the neckline and the arms. I then stuffed quilt filling between the two and sewed them together at the bottom as well. The fold of the "man boobs" and the belly button were created by pulling some thread through from the top layer to the bottom one and tying it off. A pink highlighter made the nipples.
For the bottom half, I took a pair of pajama pants and sewed them together with a pair of off-white pants I'd found and dyed the same beige. Again, I stuffed quilt filling between the two layers. As with the belly button and "man boobs", I pulled some thread through at the back seam to create a "crack" where the black thong would lay. I then sewed a piece of black fabric to the bottom half. I bought a pincushion, which I put underneath a black skull cap and tied off with a hair band to create his "hair" with the bun.
We had to "practice" wearing this Homemade Baby Sumo Costume. He hated it at first because it took some work to get into, but after a few times on and off it got easier, and he learned to like it.