“Take it easy” is the Alpha and Omega of Yukkuri speech, the spoken embodiement of all what a Yukkuri strives for in life. It's also somewhat an untranslatable pun about the "Yukkuri" word, that's japanese both for "Taking it easy", both for "Taking it slowly", thus cementing the idea of Yukkuris as lazy creatures who like to enjoy a slowpaced, easy life.
The phrase is used to identify other Yukkuris, as the Yukkuri who so answers is a sane Yukkuri. It can also be used on humans to calm them down. For example, if a Yukkuri sees a stressed or angry human, it will tell them to “take it easy” with the shitheads berating the supposed inabilty of the "Mister/Miss Human" to "Take it easy", and the niceheads actually believing to relieve the "Human" stress by sharing their easiness and reminding the Anon the value of Easyness.
"Take it easy" (slurred in "Chake id eaji") is the very first sentence a koyukkuri utters at birth, both as a loud proclamation of its objective in life, both as a request of confirmation: a koyukkuri who's not instantly greeted by a loud "Take it easy, little one!" from its parents and "sisters" will be greatly saddened, acting grieving and distressed, feeling lonely or refused, unsure about its ability to live a fullfilled and happy (thus "easy") life.
It's not uncommon for an orphan koyukkuri spending its (often short) life under the delusion that, by trying with all its strengh to thrive and be "easy", its lost family will come back, and it was left behind because of its uneasiness.
"Take it easy" is also part of the general concept of "Easy". Basically, a Yukkuri that can "Take it easy" is Easy itself. Thus being "Easy" means meeting all the requirements for an Easy Life, the ability to enjoy life at the fullest.
A nice food is described as "Very Easy", as a nice home: thus because Yukkuris have a basic grasp of the need of shelter and food as necessary to lead a fullfilling, nice life. For the same reason, a foul tasting food will be deeemed "uneasy".
A properly accessorized Yukkuri is "Easy", for example, whereas a Yukkuri with missing, misshapen or damaged accessories will be deemed "Uneasy": thus because its lack of an appreciated body will hamper its ability to lead the communal live that Yukkuris enjoy.
To a Yukkuri "Easiness" is a sort of status: as such "easy things", much as human "Status Symbols", are items that show off their "Braggable" ability to take it easy. When a Yukkuri does its home declaration, for example, it's not only claiming a nest for its own, but securing its own ability to find, own and maintain a place (even if a small nest or an improvised kennel) that, due to its inherent characteristic (a place offering an higher view point, a tight, secure nest, a corner fitting its size that prevents predators and humans from reaching inside) allows for an "Easier" life, and as such is desired and envied. As such, when a Yukkuri finds a tasty food, it may deem it easy for its taste, but also to point its ability and its "right" of having something that other Yukkuris don't have, and defines it as leading a better life.
Even family relationships are somwhat decided by Easiness: a Yukkuri parent will always be prideful about having lots of "Easy Little Ones", believing that their "Easy" qualities are a byproduct of its ability as a parent.
A Yukkuri lacking what it believes necessary to live at its fullest may deem its condition "Uneasy", and develop "Anti-yukkuritis", a deep state of depression, or actively try to "Take it more Easy", improving its condition by seeking out the missing factors to its easiness, such as proper food, shelter and companionship.
For extension, an ill Yukkuri may be also deemed "Uneasy": but whereas some Yukkuris would be deemed just "Too uneasy to live", and killed on sight, some other Yukkuri will still be cared for: a Yukkuri may ask help for its "uneasy" koyukkuri, thus implying its offspring is ill and needing medical care.
However, while a Yukkuri will be always ready and willing to flaunt its "Easy Things" to measure its easiness, it will be as eager to hide its failures. As such, after a failed Home Declaration, a Yukkuri will never blame itself for the loss of its "Easy Place", but always blame the "Uneasy Mister Human" or the "Uneasy Yukkuri" who drove it away, whereas the parent of an ill, handicapped or accessoryless koyukkuri will be more willing to abandon or kill its offspring and "Start over" by trying to have more healthy "little ones" than openly admitting to have a damaged offspring, or to be a bad parent, most likely to have caused its sufferings.
Also, "uneasiness" and "easiness" may refer at life as a whole: a dying yukkuri will always cry how it "Just wanched to chake eaji more...", and, especially a koyukkuri speaking of its dead parents, would refer to death as "The Big Easy", "Taking Easy Forever", or "Taking Easy in the Sky", thus implying some sort of spirituality geared towards the "Take it Easy" as the ultimate reward.
Not every Yukkuri however puts "Easiness", thus "Take it easy" at the core of their values and vocabulary. For example the energetic Chens, unable to take life "Easy" or "Slowly" at all, prefer to put the "Get it" as their main value and catchphrase, praising their ability to solve every problem they're faced with at once. Some other Yukkuris, as Alices, would add definite requisites to their "Taking it Easy", such as being "City-Sect", that is acting polite, refined and "ladylike" while taking it easy with others.
“Take it easy” is the basis of the Yukkuri meme, endlessly repeated by every single Yukkuri, save for Yukkuri Chen, as mentioned before, and the often mute Yukkuri Meiling.
A Yukkuri’s goal is to take it easy, things such as having a peaceful life, eating, having children, all of which achieve this goal. They don’t have anything else in mind. Funny enough, if a yukkuri hears “Take it easy,” it will answer immediately with its own catchphrase, for example, “You wanna fight!?’ for Mima-types and “Take it easy” for Reimus.
A Yukkuri will protect the "Easiness" of itself, its clan and its family with ever mean possible, even almost suicidal ones, such has making an home declaration in a human house to provide its family with a new "Easy Place". The most intelligent Yukkuri will however be willing to sacrifice some of their "Easiness" to protect the general "Easyness" of their family of clan: for example, while eating to heart's content is an appreciated form of "Taking it Easy", a parent Yukkuri may give all of its food to its starving children, thus sacrificing its easiness to let tham truly "Take it easy". While an "Uneasy" Yukkuri is usually seen as distasteful and damaging for the average "Easiness", the immediate family of an accessoryless Yukkuri may seek a replacement for it, putting efforts into restoring its "Easiness", and feeling "easier" themselves for their success.
The ultimate forme of "giving Easiness" is embodied by the Dosuyukkuris, often going to great lenghts to ensure the happiness and the well being of their entire clan. By sacrificing their personal "Easiness", they achieve the role of Dosu, becoming the polar opposite of shitheads, who instead keep living an egoistical life, reviled and feared by niceheads because of the great lenghts they go to steal easiness from others (such as hoarding food, doing home declarations in other Yukkuri's Easy Places or carelessly endangering the entire clan).
Despite "Taking it Easy" entails the indulgence into laziness and peace, values mostly embodied by Yukkuri Reimu, a mother Reimu may be angrily scolded by a father Marisa for taking "too easy", while neglecting its parental duties, thus stealing away their offsprings' general easiness.
Yukkuri have also some activites that add greatily to their easiness, mostly related to their physical beings: a Yukkuri will feel "Taking it easy" especially when eating, excreting, refreshing and living with other Yukkuris.