Appropriateness of adult males kissing their teenage sister on the lips?

[flopsy4]

Do you feel it is appropriate for adult males over 18 to regularly kiss their teenage sister on the lips "as a sign of affection?"

[Kevin Kennedy, Ph.D.]

As a rule, such display of affection is not a good idea among teenage siblings because of the heightened sexual impulses of the stage of development. But traditions vary among groups of people and among families within groups. A quick 'peck' on the lips would not be regarded as problematic, for example.

[B4Real]

There is no appropriate time for a sibling to kiss each other on the lips, that is incest.  Give a hug or if you just have to kiss, kiss them on the cheek.  For you to even ask the question is quite frightening.