Ive heard of waggling as this
imagine a dog. that has a female dog holding a huge bone for him. what happens....not that you sickos. his tail wags like mad weather there is stuff in the way or not. So what waggling would be is using one finger and smashing it back and forward. kinda like fanning the trigger but you are using the bounce back on your finger from hitting the guard to get additional speed. Alot of people who suddenly get a burst of speed while playing find that they were bouncing back. This works really well if you have gloves that are full finger. Try it some time you can get pretty good bursts of speed. comparable to a really solid fanning. Walking needs to get started up and some front players have a hard time getting a fast enough rythem in the brief instance that someone is poking out. thats where waggling comes in. burst of random speed off of mainly adrenaline.
raking is when you pull your finger verticle of the trigger. you need a ridged or winged trigger to do this you just rub up and down and it shoots at a high speed..few people do it well and even less do it well in a game. not much practicall use other than wasting paint in the staging area.