It is well known that elven ears are an erogenous zone, similar in function to human breasts or dwarven beards. This has led to many of the differences visible between human and elven cultures - sexuality being such a driving force among both people.
For instance, many elves consider the human habit of earrings and other adornments to be highly questionable. The equivalent would be a human woman walking around with her nipple piercings clearly visible. Conservative elves have a word for this which is neither translatable nor, unfortunately, printable. Similarly, the habit of some humanoids to collect "elf ears" to prove that they have killed an enemy is the cause of great animosity - an elf without ears is somehow much less of an elf.
Another consequence is that among conservative families, the women are expected to keep their ears hidden, lest the sight of their pointiness cause males to lose all control. There are several ways to do this - ear-muffs is common in cold climates while specially constructed ear sheathes are favored in warmer lands.
Of course, among less conservative elves (including the rare families who consider gender to be so unimportant that they have done away with it entirely), ears are usually left uncovered. Perhaps not coincidentally, the inter-racial barrier is more often breached in those families, leading half-elf/half-goblins and other even stranger beings.
During sexual arousal, the elven earlobe becomes engorged with blood, increasing up to two or three times. Rubbing it is understandably enormously pleasurable and can lead to climax with no other stimulus being necessary. Interestingly enough, many elves develop a fascination with ear wax and carry the wax of their beloved in small amulets close to their heart.
(from "A beginner's Guide to Elves)