Seeing all the boys covering up their erections, you decide to have some fun. Quickly, you pull on the waistband of your still unchanged boxers, turning them into a red thong sticking out over your pants. Now, it's time to mess with the boys, you make a pulling motion with your hands, stretching every boys' cocks a few inches, making it ever harder(no pun intended) for them to cover up their boners. Then, you mimicked turning on a falcet for a few seconds, filling their balls up with cum to about the size of eggs, which also made them even hornier. You felt a little sorry for the already well endowed boys, but not enough to do anything.
Now that almost none of the boys could hide their erections that could make pornstars jealous, you turn your attention to the girls. They had stopped paying attention to your more 'in depth' Sex-ed class and were now starring at their male classmates, or more specifically their bulges. You suddenly get an idea of how to get their attention back, but you need to change your outfit first.
While you love look of your jean shorts, they are too constricting, especially for what you plan to do. You turned your back to the class and bent over to adjust your pants, giving the whole class a clear view of you magically enhanced ass. With a nice tug on the bottom, your shorts lengthened and changed material into a pair of mid calf yoga pants. A quick pull has turned your white tank top into a tight crop top. You finish off your clothing changes by stomping your heels into running sneakers.
You turn back to the class, seeing that somehow the boys were even harder, with quite a few pretty obviously stoking themselves through their shorts. You look down and realize that, when pulling down your shorts, the waistband came down, showing your new ass to the whole class. "Oh, pardon me!" You said in your new voice that you still aren't used to. "Now who can answer a question." All the boys put their hands up before even knowing the question. "What happens to men's dicks when they're horny?" You can say whatever you want, so no need giving scientific names.
You look over the crowd and notice James, a friendly boy who was always shy. "James!" You call out, "care to tell the class?"
"Ummm...they get an erection"
"Come on James, don't sound like a nerd. Call parts what they are. And stand up so everyone can see you"
James goes beet red as he stands up, failing to hide his now massive dick, and probably solving any girl problems for the rest of his life"
"They're...Cocks get hard"
"Greate job James, here's your reward."
You pull the top of your pants down an inch and grab the top of your thong. With a form pull, your underpants are magically pulled through you. You then give James a sultry look as you slingshot the thong to him. He quickly puts them in his backpack and continues stroking himself through his pants.
Now you're ready to put your plan into action. "I wish that over the course of the next four minutes, I will grow a dick down to my right above my knee as thick as a soda can, with balls the sive of apples. Everyone in this will be sexually attracted to me and won't notice I changed." Then you continued your lesson, 'accidentally' giving students looks down your shirt and pressing your ass in someone's face when leaning over to help the person next to them.