This phrase is used to describe someone that acts like they are the king shit and wants everyone to know it. You can tell they are like this by the way they walk, talk, and act. Their huge ego is astounding because a lot of the time these people think they are better than everyone else.
Katie: "Hey girl, look at Molly over there with her new North face, Uggs, and yoga pants. She is sooo popular, I wish I was as cool as her."
Amy: "What a fake, she is about as cool as a tool."
Means 'Wear A Condom' In A Nonchallant way, so your teachers/parents/boss/anyone else you dont want to kno ur gona have sex, wont notice what your REALLY talking about.
*In The Middle Of A Test.* guy1 "so mann, i was thinkin i was gone "hang out" wit Leah tonight.
Guy2 "hey, Be Cool, Bag Your Tool."
*Teacher looks confused and walks away.*