Tightly wrap an elastic athletic bandage (like an Ace bandage) several times around the helmet and your back. Use as many layers as you need to secure the helmet and make the bump look smooth when a shirt is pulled down over it. Secure the helmet with some of the masking tape from step 2. Layer a few tight bandeaus over the helmet to keep it in place.
Avoid throw blankets that have a long fringe on them, as it might make your belly look weird.
Lay the blanket flat on the ground or on a wide surface like a bed or tabletop. Carefully fold each of the four corners toward the center of the blanket until all four corners touch. Remember making origami fortune tellers as a child? Imagine you’re doing the first folding step with this blanket. The result should be an uneven diamond or a square, depending on what shape your original blanket was. Don’t worry if it’s not a perfect square — that doesn’t matter.
Place Blanket 2 in the center of Blanket 1. Take the four external corners of Blanket 1 (not the four that are already touching in the center) and fold them over the bulk of Blanket 2, creating a little cover around it. Secure the ends together with masking tape, using enough tape to guarantee that the ends won’t come loose.
Tightly wrap an elastic athletic bandage (like an Ace bandage) several times around the blankets and your back, using as many layers as you need to secure the belly and make it look smooth. Secure the blankets with some of the masking tape. Layer a few tight bandeaus over the blankets to keep them in place.
If you want a huge belly, then go ahead and inflate the ball all the way. It will look cartoonishly large for a pregnancy, but that might be what you’re going for with your costume.
Make sure to point the air nozzle down toward the ground. If it points out or up, it will be noticeable through your shirt, and if it points back toward you, it will irritate your skin and start hurting after a little while.
