Well, it's a decent start.

Here's some ideas on how to improve this first scene.

I would encourage you to load this scene back up and continue where you left off, taking another angle of the head explosion, maybe in slow motion - after all, her head popping is the main event. After the head explodes, you can go for a few more seconds, showing her convulsing corpse and panning around the scene, maybe even have the man finish himself off with her corpse. Any or all suggestions would make the scene more erotic, ofcourse assuming that is what you want.