Definitions by i heart RBT

RBT 

Really Big Tits

yo check out those RBT over there.

I was looking at this girls facebook and she had some RBT

RBT by i heart RBT June 5, 2009

RFBT 

Really Fucking Big Tits

Yo your gf has some RBT, but damn her sister has some RFBT

RFBT by i heart RBT June 5, 2009