狗见狗都是舔人见人都是演
[gŏu jiàn gŏu dōu shì tiăn rén jiàn rén dōu shì yăn]
This implies 'Dogs licking each other when they see each other and people putting on a show when they see each other'. Used to comment on human behavior - just as dogs act naturally around one another (by licking), it implies humans should be more honest and authentic, rather than acting in insincere ways (putting up a front).