Chrissy dropped her napkin.

Just then, I realized Chrissy, my kid sister, had begun to climb under the table. Oh shit!

"I dropped my napkin," she said daintily. She was too short to pick it up by just reaching under the table so she began to descend under the table completely to go retrieve it. Oh shit, oh shit, I can't let my sister see my exposed, erect cock under the table! What to do? Act fast!

I deftly picked Lauren's hand off my cock and draped my napkin over my penis. Whew! Crisis averted, I think. I just hoped Chrissy didn't notice anything suspicious.

Suddenly, Lauren's hand began stroking my dick through the napkin. Oh no! What were you doing, you bitch?! I thought as she seemed determined to expose me. I couldn't get her to stop or she might take the napkin off, knowing her. Too late to do anything now, my sister popped back up at the table.