Why is it that with birthday cakes you can blow on them and spit on them and everyone rushes to get a piece?

Kelton’s joke points to a familiar social contradiction: people are normally disgusted by saliva and “germs,” yet a birthday ritual invites someone to blow directly over shared food and then everyone happily eats it. The humor comes from deflating the sentimental aura of birthdays by describing the act in blunt, bodily terms (“spit”), exposing how custom and celebration can override everyday hygiene instincts. Implicitly, the line also comments on how group rituals create permission structures—what would be unacceptable in ordinary contexts becomes not only tolerated but eagerly embraced when framed as tradition and communal joy.