The anatomy lesson

As you can see, girls, as you slide the frilly knickers down his legs, there's an interesting effect cause by the sensation of the satin rubbing against the silk of his stockings. He'll blush, but at the same time his little penis can't help but stiffen.
This is entirely to be expected when your sissy secretly wants this humiliating experience – as is the case with our sweet “volunteer” here. I'm sure the sissy that's assigned to your for your homework project will react in exactly the same way.
What's vital to remember is that your sissy must be bent over, legs spread as far as the knickers around their ankles will allow.
Come on sissy – wider.
And you must also ensure they spread their buttocks nice and wide for you. That's it, girly. Hold them there.
I can't stress the importance of lubrication highly enough here. If you don't apply it generously around the sphincter, like this.... then you're not going to be able to slide your fingers in smoothly. Ahh, there – like so.
Don't worry too much about finding the prostate as you first enter a sissy. There's plenty of time to take nice, even strokes before you start moving your fingers in search of it. You'll just need to keep your fingers moving inside them until – yes, there it is. You'll find the drool of seminal fluid from the tip of the penis will clearly indicate you're hitting the right spot.
But there's no need to worry about the mess. With your other hand, you can scoop up the mess before it becomes a problem and... well, like this sissy they may be reluctant but after the first few times they'll lap it up eagerly.
Oops.
But if, like sissy here, they ejaculate onto their stockings then there's only one thing for it. A good, hard, over-the-knee spanking followed by the rapid application of an anal plug. Not only will they soon realise they shouldn't orgasm without your permission, they'll also loosen up nicely for when you decide the time is right to deflower your sissy with a dildo.