Keeping lips hydrated all the time is the key

[Ältai.Anabolic]

For it to looks bigger/wider creating an illusion of smaller nose

 

[EvangelicalRapist]

it's not key it's basic primate technology, even people who are not hygienic use lip balm because nothing feels worse than dry lips

 

[Orc]

you can also brush them to temporally increase blood flow.

 

[bimaxenthusiast]

water (literally)