Prerequisites:
You should at least be comfortable with forward and back flips. You don't really need to know how to fly inverted to learn tic tocs, but it certainly helps. The better you are at controlling any type of inverted flight or hover, the easier tic tocs will be.
Tic tocs are deceptively simple looking. You'll find it's a lot more involved than just yanking the stick back and forth and jamming the throttle up and down. I'll show you how to break it down so you can learn how to control the collective stick seperately from the cyclic.
Starting out:
I'll talk about tail down/nose up tic tocs (aka elevator tic tocs) since most people will probably be most comfortable starting with these since the tail is mostly pointing in a direction you're familiar with.
Get to a comfortable altitude upright and tail in.
Give a little bit of positive collective
Pull back and do a half back flip until you are inverted nose in.
Give a little negative collective to catch the heli and hover inverted nose in.
Stay there for a moment and get the heli stable
Then go back
Give a little bit of negative collective
Push forward and go back to upright tail in.
Give a little positive collective to catch the heli and hover upright tail in.
Pause again. Regain control, then repeat.
While not exactly tic tocs, doing this will help you learn the coordination needed to control the collective independantly of the cyclic. At first try to keep all the collective movements seperate from the cyclic movements. You'll soon learn to apply collective based on what the heli is doing, not what the cyclic stick is doing. This is what we call "collective management"
Keep doing this and your collective management will get better and better. Gradually start catching the heli earlier so that its more at an angle at each half instead of a full half flip.
You can practice other orientations of tic tocs the same way (nose up, down, left or right). Just start upright and always flip or roll the heli towards you to inverted. Then flip or roll back.
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That's the easy part
Now comes control. In order to properly control your tic tocs you also need to learn to apply rudder and other cyclic movements at the same time you are doing the tic tocs themselves. Rudder movements allow you to move the tic toc left or right, and cyclic movements can rotate the heli to keep it on line.
For example:
If you applied some left rudder in a tail down tic toc the heli will start to drift to the left. Right rudder will steer the heli to the right. Also if you use some left or right aileron it will rotate the heli to the left or right which will allow you to keep the heli straight if it starts to rotate in an undesired direction (it will).
If you are doing aileron tic tocs then rudder will still have the same effect, but now you'll need to use elevator up or down to keep the heli straight. What cyclic corrections you'll need during a tic toc will all depend on the heli's orientation. If all that sounds complicated it really is. There are actually 16 different basic orientations you can tic toc in. There's 4 heli orientaions:
Skids away (the standard tic toc orientation)
Skids towards
Skids left
Skids right
And each one of these has 4 basic nose orientations (up, down, left, and right) Getting profecient at all of them is likely years of work. Just stick with skids away to start.
Trying to do tic tocs along with rudder corrections, and cyclic corrections all at the same time is extremely overwhelming at first, so when starting out try to just make tiny corrections on one side of the tic toc only at the slight pause in-between going from one side to the next. All I can say is practice this a lot, and eventually you'll learn to integrate the corrections you want in with the tic tocs themselves.
Hope this helps. Work on the basic at first. Then worry about control later. Soon you'll be doing stationary tic tocs right off the deck.