Using all the strength in your legs, you jump off the Jello and reach for the hole. This proved to be to difficult, and your body quickly fell back down. Because their was Jello instead of something solid, you slid right through it from your mass and high speed. You didn't pass through, but you made it quite deep, and you were unable to climb back up. Under you, the acid continued to rise, which caused you to panic. Your cries of Terror, and cries of pain once the acid reached you, fell upon deaf ears. As you were melting, Rachel was just finishing her favorite show.
After said show, Rachel glanced at the clock. Realizing it was late, she turned off the T.V. and went upstairs. After changing, she soon fell asleep in bed from her full stomach and general sleepiness. You, sadly, weren't having such a peaceful time. About the time Rachel fell asleep, the acid had reached your chest, and from then on it was a peaceful night for her stomach, quickly digesting its dinner.
The next morning, Rachel was greeted with a surprise. All of her panties barely would fit, they were tighter than usual. The same went for her pants, which led her to realize her ass had become fatter. She ( and you) had taken pride in how fit her ass had been, and this upset her. Not only that, her pants were meant to fit tight before, and now they would rip whenever she bent over. She was forced to wear larger pants until she could work the fat off.
Your failure in jumping resulted in your digestion. The usable parts of you, along with the Jello, was turned into fat. Sleeping doesn't take much energy, so her body stored it on her ass. Although you aren't around to experience it, at least your on your favorite part of Rachel.