Taki Is A Cuddle Glutton

Taki enjoying his daily scheduled cuddle session. Please note that I am restricting petting to the head only. Virtually every part of a bird besides the head and feet are a "no-no" area to pet. Petting the wings, under the wings, the shoulder blades, the back, the tail, the back above the tail, and the lower tummy should be strongly avoided as it can trigger hormonal aggression in your bird. Many birds pet in that manner excessively scream or pluck due to building frustration and they can also exhibit extremely aggressive behavior toward their owners in the form of biting. In addition, this can encourage nesting and egg laying in female birds, which also increases hormone related aggression, and can dangerously deplete the bird of important nutrients such as calcium and result in cloaca prolapse, egg binding, and numerous other health problems if repeated laying of unfertilized eggs is allowed.
Birds who want to be pet do not care whether you pet their head, their wings, their back, etc.- they simply want to be pet and be showered with attention. Your bird will not miss back or wing petting and their behavior will improve by sticking to petting the head only. If you get easily bored petting the head only, you can gently dig through the head/neck/cheek feathers for pinfeathers that are ready to be preened and preen your bird's feathers for them. This is an incredibly bonding activity that your bird will appreciate infinitely more than being pet on the back or on/under the wings.
Lastly, it is important to note that many people go out and get a bird, cockatiels and other members of the cockatoo family in particular, because they want a cuddly bird to pet and love. Not all cockatiels, large cockatoos, or birds in general enjoy being pet. If you cannot live with the idea that your bird may never allow you to touch them, please do not get a bird. Every bird needs to be tamed to every individual they will be expected to interact with, whether they're hand raised or parent raised, babies, adults, rescue birds, from a breeder, what have you. Birds who are worked with on hand taming daily can take as few as little as a month all the way up to 5 years to become comfortable with hands, and this fact is true regardless of where you got the bird, how old the bird is, or how it was raised. You WILL need to hand tame the bird before it will allow petting even if it's a handfed baby. There are playlists about how to do that properly on my channel.
NEVER force a bird to do anything it does not want to do, whether that's stepping up, being pet, taking a bath, doing a trick, or anything else unless it's medically necessary and done by a licensed and board recognized avian vet. Birds can be trained to allow and even enjoy nail trims, petting, etc. but you must train them PROPERLY, let the bird work at their own pace, and never force them to do anything during training. A bird forced to do something may let you do it, but it allows whatever is being done not because it enjoys the situation but because it feels helpless. Birds forcibly hand tamed develop a very weak bond with their owners based on fear and a feeling of helplessness. They also bite MUCH more often because there's an inherent lack of trust in the relationship, and generally owners who have an attitude that would allow them to forcibly hand tame a bird don't handle the bird in a way that avoids biting. They also typically punish the bird for biting and/or incorrectly discourage biting which can cause them to bite even more and even harder. Please take the time to learn how to properly tame your bird without using force so that you can develop a positive, loving relationship with mutual respect. If you do not have a bird but are interested in getting one, please do extensive research about their dietary needs, their behavior, proper behavior modification techniques and training techniques (taught by certified avian behaviorists/trainers who received their certification or were recertified in the last 5 years). Birds require a LOT of work, a lot of attention, an extremely specialized diet, and live anywhere from 20-80 years depending on the species.

[@Denis_Korchagin]

Cockatiels are the best parrakeets :-)