What the song is about: why some pleasures need two people
Küssen kann man nicht alleine builds a playful argument around companionship. The narrator lists activities that work perfectly well alone, then concludes with a smile that love, flirtation, and kissing follow different rules.
Learning German with Küssen kann man nicht alleine: man and modal verbs
The central structure combines the impersonal pronoun man with the modal verb können. Repeating kann man nicht alleine helps learners form general statements, place nicht correctly, give a light-hearted argument, and build vocabulary for romantic interaction.