Bob may have a Precocious Crush on older Alice. Or Alice may have a Celeb Crush on the famous Trope Troperson.
Either way, if the object of desire is particularly pleased, affectionate, or otherwise inclined, sometimes they'll give their admirer a kiss — or simply touch them. And the admirer will so treasure the moment and the memory that they want to keep the spot of the contact untouched [...] [tvtropes.org]