rock tit 

Rock tit is what happens to your nipples when they get cold, or in some cases, when one gets horny. Rock tit is characterized by a sudden hardening of the nipples, hence the name.
More "severe" cases of rock tit, where ones nipples are so hard they could shatter bones, is named "Diamond tit".

Joe: Dude, you should have put on a better shirt for today.
Hal: Why's that?
Joe: It's cold out and I can see your rock tit.
Hal: Aww shit!
Joe: Attractive.

rock tit by LordFishstcks July 17, 2007

Rock Tits 

Ridiculously unattractive fake boobs; breast implants looking as though ready to pop if touched.

Chris suffered a fractured penis while attempting to screw Michelle's rock tits.

Mike chipped a touch on Carrie's rock tits during foreplay.

Rock Tits by Charles Campbell September 3, 2005

rock tits 

When someone's nipples become hard and pointy either because they are cold or because, in a girl, they are aroused.

Bethany's rock tits were a clear indication that it was getting cold out side.

rock tits by Jaymz T July 10, 2007

Rock Tits 

When a person (typically a bro) is worked up and needs to calm down. See also Chill yo tits.

Dude, you need to heat your rock tits. I was kidding you bitch.

Rock Tits by themaninblack12345 December 2, 2011

rock dem titties 

A popular expression used to describe the sexual act of tittie-rocking

Bitch I'm gon' rock dem titties!

rock dem titties by titrocker69 July 6, 2008