Her Present

Jon suddenly felt a strong urge, and sat up straight, swinging his legs off the bed. He reached forward and pulled down the waistband of Zoe's boxers, and saw a large erect cock spring out. Jon knew exactly what to do as he placed his lips over the tip and began to move his head up and down, rubbing the shaft with one hand and gently playing with her balls with the other. Zoe began to moan with pleasure and as shedid she began groping her breasts.
"mmm that's it Jon baby." She cooed. In no time at all Jon felt a strange warmth in his mouth as his sister shot her load. Not knowing what to do, and feeling slightly disgusted he swallowed it.
"Now that's why I married you" Zoe smiled, "You always know how to get rid of my morning wood. You go have a shower and I'll go wake the kids" She added as she adjusted her boxers. It was then Jon noticed how masculine and hairy her legs were compared his smooth skinny ones. It was almost as though they had swapped bodies from the waist down, what was going on?