Over time, particularly by the turn of their first century in the UTO, perception of humans could be best summed up as an 'affectionate respect.' The size disparity and their perseverance in overcoming the handicaps that formed and turning them to their advantage has earned them a reputation for tenacity and an ability to work through any problem. The Annelid War, where humans proved to be a critical factor in hunting down the Worm Queen, gave them a reputation of aggression and courage despite their size, something the military already knew about through the Rynar War for Earth. Without question, humans came to be looked upon as equals by the other species, with those that may not being among a very small minority.
The 'affectionate part of this respect, however, is heavily tied to their size. Most people feel a certain protective urge toward their smaller friends, and many perceive them as 'cute'. Many humans may indulge in these feelings, finding a lot of amusement and fun in it. However, sometimes it can cause issues in being taken seriously, so most humans with experience working outside their species have developed a knack for being extremely bold for their size, knowing when to push back against someone that might be being too delicately careful or adoring to the point of detriment to the human's authority or self-respect. A human that feels demeaned is more than likely going to voice this, which can set the tone of many human/nonhuman relationships. Humans will demand respect if they feel they need to, and far more often than not, a nonhuman will have the respect for the species to listen.
Physical Interaction
One of the first rules of interacting with humans, isn't quite interaction at all, but a general rule - no humans on the floor in any space intended for nonhumans. In the unlikely event a human is ever found on the floor, the street, the sidewalk, or wherever paw traffic might go, the nonhuman is expected to assist and carry them to a safer location. If the human, for any reason, refuses this assistance and will not return to a human-safe area, then the nonhuman should stay and keep watch after calling for law enforcement services. The human may be charged with negligent behavior depending on what was wrong. Even if the human didn't care what happened to them, their behavior would risk someone stepping upon them, a typically traumatic experience for the nonhuman.
Exceptions apply when both parties consent to placing the human down on the floor of a private space. This typically precludes games as simple as hide and seek to roleplaying predatory games. These kinds of games are not uncommon among friends or guardians and charges, but it is encouraged to do them in the simulations.
General Handling
As a start, it is frowned upon to grab an unfamiliar human, instead of letting them climb into a palm themselves. Consent is required, and one can face legal repercussions, particularly if harm was inflicted, if they forcefully grab a human. Nonconsensual grabbing is typically a misdemeanor offense. In an emergency, consent is implied. Familiar friends may likely have a casual grabbing relationship. Public grabbing with the human not showing any signs of distress is fairly normal, though most humans prefer their friend to move them into the open palm carry when talking with anyone unfamiliar.
Etiquette for grabbing calls for allowing the human to raise their arms before closing the fingers around them, leaving their arms free to movement and for the extra security of keeping themselves up.
The standard carry for any human regardless of familiarity is in an open palm, tucked against their carrier's stomach, with the thumb in front of the human. This allows the least amount of strain on the carrier's arm, and provides a solid wall behind the human passenger with a barrier in front of them. Single hand carry is typically fine, though the carrier should alternate if the strain becomes a problem. Many humans or carriers will prefer two handed carry, with the off-hand cupped around in front of them. Anything more intense than walking will likely call for a grab carry.
In group situations, such as friends lounging at home or out at a restaurant, it is not unusual for the human to find themselves with different friends throughout the evening if they decide to go without their mech. Each nonhuman, if they are comfortable with handling humans, may carry their friend as needed. During idle moments, the human may end up in laps, on shoulders, occasionally on heads or snouts, it all depends on what everyone is comfortable with. Casual dangerous handling such as on top of heads or shoulders is typically taboo in public, however.
As an alternative to simple carrying, carrying pods exist. These windowed containers clamp onto a nonhuman's body on a specialized mounting point, most commonly on the chest. Most humans absolutely resent using these, as they are considered highly undignified and restraining. More often, carry pods are used for transporting the injured or for moving a human through an extremely busy area or event or anything that would otherwise make carrying them by hand dangerous or unfeasible. Other times, they may be used for carrying a human and their very young child at the same time, for better security. They are also sometimes used for transporting exceptionally intoxicated humans where they often end up falling asleep inside. This has earned carry pods the the nickname of 'drunk tanks' from humans.
Physical Play
Physical games between nonhumans and humans became quite popular even in friendships, not just the guardian and charge pairs that the idea arose from. Predator games remain amongst the most popular.
Predator games are typically a hide and seek type of game, where the human hides from the predator, who is likely very teasing over the whole thing. Sometimes, it might be a playful pursuit, though that requires the nonhuman to move slower, as a human simply cannot outpace them. This kind of roleplay is considered dangerous, but the laws of consent mean if the human wants it and the nonhuman agrees, there is no issue. Most humans prefer to play this in the simulations for this reason. It's the thrill seekers that may prefer doing it for real, considering the whole ordeal something like a trust exercise.
Trust exercises are another type of physical play that arose out of guardian and charge relationships, where they were originally used as a way to demonstrate the lack of fear a charge hopefully has of their guardian during the early parts of integration. Since then, they have become a way for the pairs, and even friends, to get a thrill out of the trust a human shows to them, with the human finding a thrill out of the physical threat of the experience, but the psychological comfort of knowing the nonhuman will not hurt them.
Trust exercises can be rather tame, such as simply teeth baring snarling at the human. Grabbing is even considered a trust exercise, to an extent. A more dangerous exercise is placing the human into their friend's open maw. The most dangerous types of trust exercises are the ones with the highest risk of an accident, such as placing one's paw atop a human. It is highly, highly encouraged not to test pressure. Improper handling is also a form of trust exercise, though some relationships may have it as regular, casual fun. Examples of aggressive handling would be snatching, arkatian tail grabs, cleavage stuffing, playful dangling, and so on.
Physically intensive trust exercises are extremely dangerous and tragic accidents have occurred in the past. These activities are encouraged to be kept to simulations, but again the laws of consent make it perfectly legal if both parties wish for it. Consent does not stop manslaughter charges, however.
Physical Affections
As polarity psychology has documented, nonhuman/human relationships often become exceptionally platonic, well before they may become romantic. Nuzzling, petting, licking, and so on are common.
This varies from person to person, human or not. Some may want nothing to do with it, some may enjoy it to an extent, some might adore heavy lupari licks. Public affection is not typically taboo, perhaps even the opposite of that at times, but the important part of it is consent. Many humans find blatant public affection to be embarrassing or demeaning, and their nonhuman partner should respect that, and refrain. Likewise, a human should not try to encourage it if their nonhuman partner does not wish for public affection themselves.
The prevalence of platonic behavior in mixed size relationships means it is very common for new friends to simply ask each other about their thoughts on physical affection to make their stances on in clear early on.
A stereotype exists that guardian and charge relationships are the most affectionate of friendships, even in the military. Most pairs may deny this, but anonymous polling has found 76% are platonic to some extent, at least in private.
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