According to Ralph Grower's Manners and Customs of Bible Times, kisses for greetings were done with a peck of the lips on the left cheek followed immediately by a peck of the lips on the right cheek. These were already the standard cultural form of greeting in Mediterranean and Semitic cultures of Paul's time, and pretty much remain so today. Paul was only adding the term holy to the cultural practice.
Given what we know about the sexual issues at Corinth, would it make sense for Paul to take up the greeting kiss and add the word "holy" to it?
Other cultures do not use a greeting kiss, however, but have other small rituals they do when greeting one another: flutter eyebrows; rub noses; rub elbows; pat heads; bow slightly; tip hats; raise hats; wave; make certain toungue-click noises; hit fists; give "fives"; kiss hands, etc. In the general U.S. culture, people shake hands.
Also, there are gender differences in cultures' greeting rituals. For example, take cultural greetings in Latin America. Males shake hands, usually by grasping right hands and then using their left hands to clasp over their joined right hands (all four hands are shaking, very firmly), often followed by a shoulder embrace; the women who know one another practice the greeting kiss the same way Mediterranean cultures do. Male and females who do not know one another greet each other with a limp shake of right hands, but the woman only uses her finger tips and thumb in the action. Males and females who are of differing age and who know each other well may practice the greeting kiss. Etc.
So was Paul meaning by his words in 2 Co 13:12 to lay down an immutable and universal command for all Christians of all times?
Or, given that he wrote 2 Co 13:12 "to the church of God which is at Corinth with all the saints who are throughout Achaia" (2 Co 1:1, emphasis added), was this something that was culture, situation, and time-space bound?
Is this culture, situation and time-space bound:
2Ti 4:13 When you come bring the cloak which I left at Troas with Carpus, and the books, especially the parchments.
Is this situation and time-space bound:
2Ti 4:21 Make every effort to come before winter. Eubulus greets you, also Pudens and Linus and Claudia and all the brethren.
Missiologically, do we madate upon elbow-rubbing, eye-brow fluttering, and nose-rubbing greeters that they must now use the holy lip-to-cheek left-and-right side kiss when they become Christians? What if I am reaching African-American street gangs, who culturally have elaborate, multi-step greetings involving hands, heads, arms, and toungue-clicks?
If I were translating the Scriptures to an elbow-rubbing culture, could I even dynamically translate the passage, "greet one another with holy elbow rubs"? Or at least when expositing the passage, could I "translate" it that way to listeners?