Combining colors by mixing up two or more batches of silicone of different colors and then blending them in different ways can produce some interesting sex toys.

Start by creating multiple batches of silicone at the same time. I've found the best way to do this is moix color into Part A (yellow) of silicone in different cups, mix it thoroughly, then combine it with Part B. You need to work reasonably quickly, because once you mix in Part B, the silicone begins to cure.

Mix Part B thoroughly, vacuum the silicone, and then pour into the mold.

How do you pour multiple colors of silicone? Ah, now that's the artistry.

Alternating colors

The simplest way to mix colors is just pour a bit of one color, then pour a bit of the other, then pour a bit of the first, then pour a bit of the second. Doing this creates a sex toy with stripes—perfect for creating, for example, a rainbow-colored sex toy. The effect looks something like this:

Color marbling

You can also create interesting effects by mixing colors in two different containers, then pouring them into the mold at the same time. Keep moving the containers as you pour them into the mold, and vary the speed with which you pour. This will create an effect where the finished sex toy has a random marbling pattern.

Vertical color bands

If you mix multiple colors of silicone and then pour them one after the other into the mold, you'll end up with horizontal stripes in the finished casting. But what if you want vertical bands?

To do that, you can carefully pour two different colors of silicone into the same cup, then pour from that cup into the mold. Be careful to pour your two colors of silicone into the same cup evenly, at the same rate, so you end up with something like this:

Then carefully pour the silicone into the mold, making sure you pour so that the line between the two colors stays centered in the stream of silicone like this:

The finished piece will have a vertical color fade like this kazoo ball gag:

Color blending in the mold

To get more precise multicior effects, such as details in different colors on the sex toy, you can blend colors by painting ir laying silicone directly into the mold, allowing it to cure, then pouring a different color into the mold.

For example, I created a silicone tentacle dildo with different colored suckers by using a blunt-tipped syringe to fill the suckers in the mold with one color of silicone, letting it cure, then assembling the mold and pouring the tentacle with a different color of silicone.

Color mixing with syringes

This technique requi9res quite a lot of patience. Mix two (or more) colors of silicone, then fill small syringes without needles with each color. Carefully squirt a small amount of one color into one side of the mold, then another color into the other side, then the first color into the same side you placed the second color, then the second color into the same side you put the first color, rocking the mold back and forth at each step. The result (with practice) is a fine, subtle swirl of colors like this gag, which was made with green and white silicone: