"Slow sync" means using a flash, but also leaving the shutter open longer, as if you weren't. This creates interesting effects with a subject in motion.

Unfortunately with my camera you can't specify (or at least, I can't figure out how to specify) whether the flash pops at the beginning or the end of the exposure. It should happen at the end, so the blurry long exposure looks like a trail behind the subject. But mine flashes at the beginning of the exposure. We got this image by tying a string around the wind-up toy and pulling it backward.

I wanted to see more than those faint red streaks behind the toy. I think we needed more ambient light.

I have duck-on-a-bike too! he was a valentine's day present. It's so exciting to see him in action like that!