Being rock solid means being well grounded with someone close to you , to be close in a friendship, relationship, etc. To stay honest, and real no matter the circumstances.
He was honest in everything he did and said, we're really close friends, I told him everything and he didn't tell a soul my deepest secrets. His character is rock solid!
when a guy sends you a dick pic with the caption solid as a rock right now ,claiming he's hard over you when reality he's a porn addict and doesn't like you sorry
Guy's Dick Pic: My dick's Rock Solid for you now baby