Before she hit the club with her boo Drake to celebrate her best friend’s birthday, Rihanna had a party of her own out in the Hollywood Hills – a no-pants party! The Bad Gal had what may be her raciest photo shoot yet (well, there were those leaked pics…), posing with no pants or panties and tootin’ that thang way up in the air! Rih-Rih is fearless! Check out the super sexy pics in the gallery. Bottoms up.