The term butterfly kiss denotes:
– a light kiss in which the lips only brush the skin;
– an act of affectionately fluttering one’s eyelashes against a person’s skin.

The earliest instance that I have found of butterfly kiss used in the sense of a light kiss is from Leaves from my Journal, by ‘Squire Outis’, published in Godey’s Magazine and Lady’s Book (Louis A. Godey – Philadelphia) of October 1848—the narrator is at the wedding of his “old crony L—”:

“What God hath joined let no man put asunder,” announced the ceremony finished.
Then awhile was silence, as it were, till the holy act had been registered above, and then what a feast of kisses and what heartfelt salutations were exchanged! There was the light butterfly kiss of ceremony, cruelly bit in twain and offered a dainty morsel; the deep, tear drawing, sunlike kiss of parents; the fervid musqueto [sic] kiss of sister and brother; and the long, long-drawn, honey-bee kiss of true friends, when lips hung together tenacious as the cockle-fish to its rocky home.

The second-earliest occurrence that I have found of butterfly kiss used in the sense of a light kiss is from Adam Bede (Vol. I – William Blackwood and Sons – Edinburgh and London, 1859), by George Eliot, pseudonym of the English novelist Mary Anne Evans (1819-80):

Poor things! It was a pity they were not in that golden age of childhood when they would have stood face to face, eyeing each other with timid liking, then given each other a little butterfly kiss, and toddled off to play together. Arthur would have gone home to his silk-curtained cot, and Hetty to her home-spun pillow, and both would have slept without dreams, and to-morrow would have been a life hardly conscious of a yesterday.

George Eliot used butterfly kiss again in Romola (Vol. II – Bernhard Tauchnitz – Leipzig, 1863):

“If you kiss him very gently, he won’t wake: you want to kiss him, is it not true?”
He satisfied her by giving the small mummy a butterfly kiss, and then putting his hand on her shoulder and turning her face towards him, said, “You like looking at the baby better than looking at your husband, you false one!”

The earliest instances that I have found of butterfly kiss used in the sense an act of affectionately fluttering one’s eyelashes against a person’s skin are from Ione (Vol. I – Bernhard Tauchnitz – Leipzig, 1884), by the British journalist and novelist Elizabeth Lynn Linton (1822-98):

“Say ‘I’se sorry,’ else I will get off his knee and go into a corner and cry,” she persisted.
“No; you shall not do that; so here goes;—‘I’se sorry,’” said Anthony, smooth as satin and soft as down.
“Good boy! Now I’ll give him a butterfly kiss,” returned Theodosia, fluttering her long eyelashes rapidly over his cheek.
[…]
That was all her reward for the trouble she had taken to get him here at all—coaxing that cross old Anthony of hers into a good humour, and making her eyelids ache with her butterfly kisses!
[…]
Anthony was cross too; but his little wife did not perch herself on his strong knees, nor join his broad hands together by the palms, nor call him her dear old bear, nor fatigue her eyelids by giving him a butterfly kiss to bring him back to good humour.

The following from The Alabama Enquirer (Hartselle, Alabama) of 8^th August 1889 presents butterfly kiss as a new term:

The Butterfly Kiss.

“Say have you got on to the latest kiss?” asked a young man of the editor of the Enquirer recently.
“No, what is it?”
“It may not be new, but I have only lately experienced it. It is called a “butterfly kiss” and is as light and airy as the name signifies.”
“How is it?”
“Well, when a girl is real glad to see a fellow’ and dosen’t [sic] want to kiss him downright, she gives him a butterfly. She gets up close to him, bends over him and lightly sweeps his cheek with her eyelashes. It’s over in a second, but it’s fine. When a girl that is just as absolutely pretty as she can be, with the loveliest eyes in the world and the longest kind of sweeping lashes, comes and delicately fans you in that style, I tell you, you feel like being lifted right up into the seventh heaven. It is something like I imagine a fairy’s visit or an angel’s touch would be. To appreciate it you must experience it.”
“But say what happens then? Don’t a more substantial osculation follow these dreams of bliss?” asked the inquisitive editor of the Enquirer, after short silence.
“That depends” was the reply, “and as I have never experienced this Elysian feeling but once, I am not going to say.”
And he proceeded on leaving the editor musing “Verily, there is something new under the sun.”