I would probably start with her head too! Not sure why, but it just seems right.
Jenny, how are you going to do it? Are you going to have him deposit his sample into a cup? And then are you going to use a needless syringe to squirt it inside of you?
If so, draw it into the syringe slowly, then tap it so the air bubbles rise to the top, then push the air bubbles out.
Then, insert the syringe as deep as you can. You want it as close to the cervix as possible. Push the syringe plunger very slowly. If you do it too quickly, all the semen will squirt out of you. Then just lie there with your hips elevated and maybe give yourself an orgasm if you can. That's it! You're done!