To rub noses with either a partner or lover, or a much loved pet animal, in an affectionate way, like the Eskimo kiss but with more gentitlity- unless it's a 'woodpecker snoo', which is a much faster, slightly more aggressive (but still pleasurable) action. Can also be the pet name of the person you regularly do it with.
"Oo oo oo, I wanna snoo with you"
"You are my snuvverly snoo"
"Snoo with that flibbly woo"