WHAT THE F*CK??? RIHANNA PULLS A 60 YEAR OLD MAN . . . 300 LBS . . . ON STAGE AND FREAKS HIM OFF!! (PICS)

Rihanna really is losing it. Last night during her concert in Barbados . . . she puled a 60 year old "fan" on stage. She climbed over his belly and RODE HIM LIKE A HORSE!!

NASTY!!!