Floyd Mayweather Jr. goes nowhere without his A.1. Steak Sauce. He and his large entourage showed up at Lavo in Las Vegas the other day to celebrate his brother’s birthday and his trouncing of “Sugar” Shane Mosley in the welterweight title fight May 1. When they were served their well-done steaks, Mayweather’s brother asked if the restaurant had any A.1. The server said no, but a bottle of A.1. was instantly produced from Floyd’s “cash bag,” a tote the boxer uses to carry US currency that he “rains” on crowds at nightclubs. The A.1. bottle was then placed as a centerpiece on the table. “A.1. was doused on every single item — chicken, steaks, even the garlic mash,” a witness reports, adding, “Floyd made a comment that he even eats cereal with A.1.” Maybe an endorsement deal could be in order — who needs Wheaties when you have A.1.?