Yeaning is initiated when the womb-nest’s heart stops pumping. This isn't immediately sensed by the kits as their own hearts pick up some of the slack, but the increased load on their hearts tells them it's time to go. This doesn't happen to all the kits simultaneously. The largest or most active kit is usually the initiator. Using their claws they pierce their amniotic sac and then the outer dermis of the womb-nest itself. If they weren't moved to act by the heart stopping, the massive increase in light pouring in through the rent in the dermis made by the first little trailblazer is usually enough stimulation to get the others stirring.
Not all litters have an obvious runt, but most large ones will. The runt is often the last to emerge, hence why the Commonthroat word for runt literally means “little last one”. They frequently need a bit of help from one of their dads. Whether and to what extent this help is given is subject to much debate in the medical community and superstitions and traditions abound. On one end of the spectrum, some say that a sire should completely remove the runt from his or her amniotic sac manually. On the other end, some say that fighting their own way out helps build the runt's weak musculature, stimulates their less robust heart and lungs to work harder, or it just builds character. Many split the difference and pierce the amniotic sac and let the kit do the rest. Which sire gets to do this is also subject to cultural particulars. Some say the youngest sire should do it, others the oldest, still others say that if one of the sires was himself a runt he should do it.
Among Sweetwater's surface dwellers, it's a common superstition that the runt (or any kit that dawdles in their amniotic sac and needs to be coaxed out) has an affinity for water and will make a good sailor. Around Moonlitter, this same phenomenon is interpreted as the kit being destined for interstellar mission work.
Smaller yinrih, often runts, are prized for their ability to negotiate tight passages. This is most relevant to the Farspeakers and their secular inheritors.
Meanwhile, the first kit to emerge has their own cultural associations. Some say they have a strong desire to witness Creation and are destined to become research monks. If they are female, it is said by some that their desire to bask in the light shows they will one day become a hearthkeeper. If male, their vigor and strength will push them to a career in law enforcement or the military, or in more pious enclaves, to the Knights of the Sun.
The sires are traditionally the first to handle the kits, the culmination of moths of diligence and protection. After toweling them off, they'll get passed around from dad to dad, getting a quick nuzzle and sniff before being handed off to the dams to be nursed for the first time. First Nursing is also steeped in tradition. The sires usually eat a huge meal and then go into torpor, both of which were in short supply during the kits' gestation.
The dams get to bond with their kits as they nurse for the first time. When nursing, the dam will lie on her back with one or two kits resting on her belly. She will cup the kit's head in her forepaw, and the kit will start licking her lactation patch. Saliva stimulates lactation. This can be the dam's or the kit's. If the kit proves particularly fussy the dam will initiate lactation by licking her paw herself. The scent of the milk is usually enough to get the kit to start licking.
As mentioned several times before, adult yinrih don't tolerate physical contact, but kits and younger pups often receive affection from their sires and dams. During nursing a dam will often stroke the kit's head and back with her thumb. This aids digestion. Just like humans, kits will sometimes spit up.
The image of a dam cradling a nursing kit's head in her paw is the quintessential symbol of motherhood cross-culturally, and has given rise to the mild oath “By the palms that nursed me!” or just “palms!”