Burn him to a crisp
From Create Your Own Story
The puddle of fun you sit in boils and steams as you turn into your true form, unleashing a blast of fiery magic. Your remaining clothes are incinerated and your hand grasps his hard cock, his excitement evident at seeing your true form which is simply a nude version of you colored vibrant orange with flaming hair and crimson eyes.
You stuff the rod up your love hole and he screams in pain, feeling himself being castrated through incineration. Finally, you have enough, shooting a compressed blast of fiery magic in the shape of a tiny shard through his heart.
Without thinking you burn his corpse, but realize he had on the only clothes in the alley. You attempt to get up, but a warmth in your now mortal body shoots down into your nether regions. The experience using your true form to sexually kill the man has excited you and now that you have returned to your mortal form you feel the need to touch yourself.