"Would you stop peeping at your little sister?" Mark growled.

"She's jerkin' off!"

"What?" He turned around and looked. Keri was lying flat on a lawnchair. He could see her legs were pulled apart, her feet off the sides of the chair. Her hands were in her crotch and… on her big tits! He swallowed in surprise as he saw her ass humping up and down, doing slow circles on the chair. Oh, God! It was almost too much to watch!

As the two of them watched, spellbound, Keri's back arched, rising high, her body bowing and holding still for an agonizing long moment. Then she dropped flat and lay still as death.

They continued to watch for almost a full minute, as if turned to stone. Then Mark cleared his throat and tore his eyes away.

"Get back to work, Joe," he growled.

"Shit! Did you see her…"

"I said, get the fuck back to work!" Mark snapped. He hammered at the joint with his mallet, trying to ignore the immense boner in his pants, and trying not to think of his little sister.

Keri lay there in the sun for most of an hour before finally picking up her things and going back downstairs. She never saw her brothers. She put her robe on. It was a cheap one, and she'd wash it later, then went downstairs again.

She got a towel and went to the bathroom to shower off. It was locked. She sighed and leaned against the wall. There was a thump off to her left, and a few seconds later Jody rushed past, flung her bag into the living room and went into the kitchen.

Jody was almost as bad as the others, Keri thought. The jerks at school were wrong to think she was a lesbian. She didn't know how she knew that, but she was certain of it.

Jody was a tomboy all right, there was no doubt about that. Keri was sure she wasn't hot for girls, though. But she didn't think Jody was hot for boys, either. She didn't think Jody cared about anything but sports. The little twerp was on every freaking sports team the school had!