When the burning remains of a joint or blunt containing cannabis are left to smolder in the ashtray instead of being extinguished, it has been tipped to Bob (Marley)
Stoner1: Anyone want to hit this roach? It's getting pretty short..
Stoner2: We're good man, just tip it to Bob.
A self-imposed drinking move exectuted by lifting (or "tipping") up the bottom of a glass or bottle by the consumer's own free hand, usually used to display acknowledged embarrassment or awkwardness, or sometimes just because.
When Richard was asked if he had slept with the fat girl, knowing damn well that everyone knew, he decided to tip-it-up instead of responding.