a phrase used to indicate that we refuse to defend a claim we've made---in other words, that we refuse to offer reasons that what we've said is true
PERSON-A: "You shouldn't hang out with her anymore."
PERSON-B: "After all she's done to help me? Wouldn't that be pretty mean and selfish of me?"
PERSON-A: "I'm *just saying*, you should quit hanging out with her."
A phrase that is used when someone is offended by something you said. This phrase then removes all the offensiveness of the previous statement, making it all good.
Ryan: That chick has nice tits!
Rob: Damn, that's my sister!
Ryan: I'm just sayin'
Rob: Oh, okay, it's cool.
kyle: butters, i think we should talk.
butters: well sure, kyle.
kyle: don't you see this is wrong? your getting little boys spending all there lunch money on kisses. it's wrong.
butters: kyle, everyone pays for kisses, do you know what i am saying? if you got a girl, and she kisses you, sooner or later, you're paying for it.