Jennifer blushed and started to pull away, but Susan deftly grasped ahold of the head of her cock, running a finger underneath the flared head, and another over the top of it, teasing the hole on the mostly flat glans. "Come on! I know you want to, and besides you don't want to have to go to the bathroom to masturbate in the middle of first period again?"
Jennifer only gasped at the new sensations, pleasure pulsing through hir groin sending blood through the member causing it to swell eagerly out of the sheath. "What right here in front of everyone?" she said with a mix of shock and intrigue.
"Why not? It's not like you haven't done it in front of everyone before. We all know that a horse's cock gets hard when ever it wants so at least out here most of it will just get on the ground, and the janitors will be happy they down have to clean up another mess." Susan giggled as she continued to caress Jen's cock running her hand still around the head, while she raised her other one, to wrap it around the shaft as a thick medial ring popped out of Jen's sheath. The pleasure was almost too much as she tried to take in all the new sensations, but she managed to restrain herself, going wide eyed as the shaft kept growing and growing until the weight of its size was too much for it to stand straight up from her dainty human crotch. It bobbed foward at a right angle from her belly, almost pulling her over again, and thick gobs of pre fell onto the ground before Susan had a chance to collect the next couple, dragging them all over the cock. The lubrication let her start to pump her hand up and down the length of Jens cock even faster, as the fully hard 3 foot length caused her to spasm and jerk a little, having to put a hand out on the wall of the school to keep her steady. She had just about gotten used to all the feelings when a sudden intense pressure built up in her balls, and they seemed to jerk up a bit, before her cock spasmed and she felt her first male orgasm, shooting a massive jet of cum out onto the ground, 5 feet in front of her, quickly followed by at least 10 more contractions, each one shooting a little less. Jennifer this time did fall, as her knees giving out stars and colors and even tastes dancing before her eyes, but Susan managed to catch her before her cock hit the ground.
"You ok there Jen? That was a really big orgasm, like you hadn't cum in forever! "
Jennifer nodded and slowly stood back up looking at the mess she had made, her powerful jet black stallion length still quivering, the light reflecting off the pre left on it, even as it began to soften and slide back into her sheath. "Um yeah I think I am, just been having some weird dreams lately, so maybe thats it...."
Suddenly the bell rang and the milling students rushed towards the doors, as did Susan and the rest of her friends.
"Come on we can't be late again! " Susan said as she dragged Jen inside by her skirt, her cock swaying as it further retreated, and oozed a sticky trail of seed.