The tingling started at the base of the inch-long organ and seemed to slowly progress along what could now loosely be term a 'shaft'.
"Ungh..." moaned Tiff, biting her bottom lip, twitching her hips and squeezing what muscles she could in her pelvis, resisting the urge to touch what was now essentially a beacon for her attention (and lust). After about 30 seconds, the tingling stopped. "Hmm... 1.5 inches... jeez, if it carries on at this rate, I'll be as well endowed as Katie by the morning..." pondered Tiff with a disappointed tone...
She stood up, pulled up her underwear carefully and retreated to her room. She noted down the size difference on a piece of paper and relaxed on her bed.
Before she knew it, she had drifted off to sleep.