Rachel's back arched sharply as I lowered my head to her chest. I first licked a slow, wet circle around her already stiff left nipple, feeling it tighten even more under my tongue.
Then I parted my lips, took the hard, wrinkled peak into my mouth, and bit down — not hard enough to break skin, but firm enough that my teeth sank into the sensitive flesh and left a clear, reddening ring of indentations around the base of her nipple.
The moment my teeth closed, Rachel's entire body jerked. A sharp, high-pitched hiss of air escaped through her clenched teeth, followed immediately by a long, broken, thoroughly embarrassed moan that echoed off the cave walls.
"Hssss…! Aaaaaah…! Nnnh… don't… aah…! You bit it… hnnn… there's going to be a mark… aaaaaaaaaah…!"
I kept the nipple trapped between my teeth for another second, tugging it lightly outward so the soft breast stretched, before releasing it with a wet pop.
