The insulting slang “kiss my ass” dates back at least to 1705

The science of kissing is called philematology.

Lips are 100 times more sensitive than the tips of the fingers. Not even genitals have as much sensitivity as lips

Approximately two-thirds of people tip their head to the right when they kiss. 

Some scholars speculate this preference starts in the womb.

KISS (v.)

O.E. cyssan "to kiss," from P.Gmc. *kussijanan (cf. O.S. kussian, O.N. kyssa, O.Fris. kessa, Ger. küssen), from *kuss-, probably ultimately imitative of the sound. The O.E. noun was coss, which became M.E. cuss, but this yielded to kiss, from the verb. For vowel evolution, see bury. There appears to be no common I.E. root word for "kiss," though suggestions of a common ku- sound may be found in the Gmc. root and Gk. kynein "to kiss," Hittite kuwash-anzi "they kiss," Skt. cumbati "he kisses."

"Kissing, as an expression of affection or love, is unknown among many races, and in the history of mankind seems to be a late substitute for the more primitive rubbing of noses, sniffing, and licking." [Buck, p.1113]

Some languages make a distinction between the kiss of affection and that of erotic love (cf. L. saviari "erotic kiss," vs. osculum, lit. "little mouth"). Fr. embrasser "kiss," but lit. "embrace," came about in 17c. when the older word baiser (from L. basiare) acquired an obscene connotation. Kiss of death (1948) is in ref. to Judas' kiss in Gethsemane (Matt. xxvi.48-50). Slang kisser "mouth" is from 1860. Insulting invitation kiss my ass is at least from 1705, but probably much older (cf. "The Miller's Tale").