You couldn't see it but you knew Emily was smiling when she said. "Your wish is my command birthday boy."
You can hear Emily masturbating and you can feel the vaginal juices slowly rising. You start to masturbate yourself as the fluids continued to slowly rise. You go at it for a while until you cum hard nearly painting Emily's vaginal walls white. You feel a slight sting at your legs, you look down and see some of the skin around your legs is melting off. But at the same time it enjoyable and so you go for round two on masturbation.
You stroke your shaft harder and faster each time until you climax a second time. Her juices were now halfway up your stomach. You can feel more and more of your flesh melting off, you look down at your legs and you can see muscle and bone. You still feel a strong sense of bliss and go for the third round. You keep stroking harder and faster and you notice that the fluids are rising faster and faster.
Emily is masturbating faster now, you can hear her moans getting louder and louder. She is close to orgasm and so are you. The fluids rise to your neck and are starting to melt the rest of your body. You both orgasm at the same time. You paint more of her insides white, while her fluids melted more of your flesh off.
Exhausted you relax in the fluids and let the rest of you melt. It feels good all the way through, uncontrollable bliss all the way through. You eventually loose consciousnesses and all of your flesh and muscle are eventually melted, leaving a few bones. Emily started to masturbate again while you melted. She came a second time and this time your skull came out along with the large amount of cum from your body.
Emily was exhausted but she noticed that her breasts and ass grew a slight bit bigger.
"That was amazing! That was a present for me on it's own, though I hope you enjoyed it has much as I did." Emily said laying in the tub filled with your liquefied remains.
Once she fully recovered she found your skull. She smiled cleaned it off before keeping it on her shelf as a trophy. She occasionally reminisces about that day and how great it felt. It always makes her a bit wet from just the thought.