Milk is thicker than water so gives better shapes than water. One on the first things most people do is start to add thickening agents to water such as guam gum. But if you are just starting out milk an gives some very good results.
I use either bulb mode or a long shutter speed. This is explained somewhere on the website (can’t remember where).
If you are a purist you can shoot in the dark but I have found a small apperture in dim light works as well.
I used lights when making the video so you could see what I was doing:-)
If I remember correctly I have the shutter speed at 500ms and had the flash trigger before the shutter closed. The benefit of using bulb mode is you don’t need to worry about the shutter speed. When using a fixed shutter speed you have to make sure the flash fires before the shutter closes.
When using the flash to take the photo mirror lockup doesn’t really help. When triggering the camera to take the photo it does help.
On mobile so sorry if there are typos.