Finishing with authority.
1 Make sure your girl isn't going to wriggle or flinch at the decisive moment. You may need to give her a sharp command - in a voice that lets her know you mean it. Or: that long hair you insisted upon might come in handy - it's amazing what effect a tightly-gripped handful of hair can have.
2 Make sure that the mouth is open. She ought to know the drill by now.
3 Steady yourself and take aim.
4 As you start to shoot, you may need to adjust slightly if the first shot misses, but there's no reason why every other spurt shouldn't go straight into that open mouth.
5 Her mouth should stay open to display the spermy contents to you. When you are ready, you can allow her to swallow.
5 Your climax has become a way you demonstrate your mastery and authority.