This is always so tricky to explain.
You need 2 cups, each w/ a diff colored soap, let it get a bit thick then pour both at the exact same time, very slowly, 1 starts at the NW corner of the mold & 2 starts at the SE corner of the mold, criss cross the cups while pouring untill you get the desired effect. If they are too hot they will blend into 1 mucky color.
You could also pour the mold 3/4 full with 1 color & let it start to thicken & come back through w/ a *hot* batch of soap & pour it around & back & forth untill you have the desired effect. The heat of the 2nd soap will cut/burn it's way into the 1st sightly thick soap.
Hope that made sense.
The above is the 1st swirl I ever did about 6 years ago. It was peaches & cream. The photo is really dark & blury but it *may* give you an idea. I learned to swirl better but can't seem to find any other swirl photos :roll: .