Gwen was always out there on the patio whenever there's good weather, taking the opportunity to read for a half hour or so, except every so often when she fell asleep in the warm rays.
Today, you decided to join her in enjoying the nice weather, with a few laps around the pool. She was already set up, and to your delight you could see she had used your tampered tanning cream. Earlier, you had swapped Gwen's normal tanning lotion for one of the experimental photosynthetic creams from work. Gleefully you hopped in and started on your routine.
Resting after your first set, you could already see the lotion taking effect. Laying face down in the lawn-chair, you had a perfect view of the new development swelling on her long, slender figure. Where once was only unsatisfying flatness, two shiny cheeks- like two halves of a basketball stuck out.
Immediately flushed with mischevious pride and energy, you went back to your laps before she could notice you gawking. You tried to rush through your set as fast as possible, but not fast enough to seem suspicious, to make her roll over or move. Again, you slid up to the side of the pool to nonchalontly mock taking your pulse.
Instead of two basketball halves, there were now full beach-ball sized globes of flesh obscuring your view. Amazed, you could see her thighs had kept pace and swollen along with her rear- into thick meaty trunks rivaling the diameter of your waist.
What was truly exciting, was to see the book she was reading loosely dangling out of her limp hand, and the other hand tucked under her head- fast asleep..