Flesh-n-Bone Gives Bill Cosby Prison Survival Tips

Flesh-n-Bone says Bill Cosby better sharpen up his checkers game, and his stand-up comedy ... if he wants to make it through the next 3 to 10 years.

We got the Bone Thugs-N-Harmony rapper Thursday at LAX and wanted to know, from a celebrity's perspective, if doing hard time is ... well, hard. Flesh scoffed at first, telling us it wasn't too tough for him -- he did 8 years for assault with a deadly weapon and a probation violation.

But, he admitted Cosby's rape conviction could make life on the inside harder for him. Flesh's survival tip for the disgraced comedian is be funny, as in ... lean on those pudding jokes early. You gotta watch Flesh's reaction when we tell him Cosby actually got Jell-O his first day behind bars.