Britney Spears flashes her butt in a tiny black lace G-string after sleepover with Kim and Khloe Kardashian 

BRITNEY Spears left little to the imagination with a nearly nude snap uploaded on her social media. The Gimme More singer, 43, posed up a storm in a tiny, laced G-string in the striking image shared on her Instagram. Baring all for her 42million followers, Britney faced away from the camera as she flashed her…