"Barely. I hope this gets better soon," she gritted out through clenched teeth, "move a little bit, let's see."

"Uuuugh," she grunted when he pulled out slightly and pressed back into her ass. He felt bad for causing her discomfort but not bad enough to keep from cumming. Early. And hard.

He couldn't help it. He'd gotten overexcited. But who could blame him? His own sister was bent over in front of him and he was balls-deep in her gorgeous little nineteen year-old track star butt.

"Are you...?!" his sister's head whipped around just as he began spewing cum into her straining rear hole.

They had taken several minutes to...