Buff bay are the words used to describe a fat juicy vagina. It originated in Hackney, London amongst a group of lads who hung out in The Pembury Estate between the years of 1989 to 2000.
"Look at the crutch on that! You can see buff bay right through the front of the jeans".
Jonny asked Alfie what the girl he slept with last night was like. Alfie replied, "She was buff and when i put my hand down her knickers i felt the sun and the sea, buff bay filled up my whole hand, it was like a third thigh down there". "So she had a fat pussy then?" said Jonny as he laughed.
"I got Buff bay right over here," said the prostitute slapping her vagina as way of indication as to how fat and juicy her vagina may be.