T-shirt slogan:
http://www.idakoos.com/tshirt+long+sleeve/kiss-im-decorous,772152
Google:
in keeping with good taste and propriety; polite and restrained.
Merriam-Webster:
marked by propriety and good taste
Urban Dictionary:
When a person is being really extra and rude but you have to deal with it
while being polite and restrained
http://www.urbandictionary.com/define.php?term=decorous