Coal let out a gasp of pleasure and pain as the potion slid down her throat and began taking effect. Xan stood by with a grin as he watched expecting something else to happen, but in the end Xan was the one suprised as Coal slowly changed back to normal.
The newly added wings and tail were the first to recede into Coal's body, along with twisting horns on her head. After that she let out a scream of agony as the potion continued its work. Her skin reached its normal tone followed by the softening of her feminine curves.
A grumbled "Damn, it wasn't supposed to do that." was all the Xan could manage, but he wasn't one to miss a good opportunity. So he started stroking his member while Coal was stuck in such ecstatic agony. Xan did have time for one more comment as Coal's breasts begins to shrink "Nothin turns me on like a good transformation."
Coal had lost most of his girlish figure by now and had started to regain his manhood. His moans had nearly returned to normal(for him anyway) when the last of the succubus's strength left him he slumped to the ground quite unconcious. Xan shot off his load, getting some all over Coal's leg with a snickered "Oops. I guess I'd better get him back to his room." With that Xan started to drag his master toward the door.