In conversation means kinda lame/second rate/uncool/weird.
B: wow this is fucking sideyyy, lets bounce
A: Wow you guys only talk with each other online?
B: thats hella sidey lol
us:''Whatever, bring it.''
clanwar goes 3-3
us:''Geezez Dude, its just a game~~''
"Yeah, he was pulling a Sidey and broke his foot...again!"