You slammed into marks backside as you felt your muscles begin to grow once more, the well-toned belly became a massive 8 pack of abs as you felt your shoulders and hips broaden as your frame gears to gain hundreds of pounds of primal strength. you have to adjust your grip on mark a few times as you grow to be 2 to 3 heads taller than Mark, his grip on the tree struggling as the tree itself was beginning to unroot itself. Your voice becomes deeper along with your breaths as your chest expands as you climax for a 2nd time into the now weaker-looking Mark. going for orgasm number 3, you find that your cock didn't fit marks already swollen and leaking asshole, its as if your cock was getting bigger.
you see that your cock had become redder, the head flatter with shaft thick and longer than you remember, your balls had swollen to the side of grapefruit, your private hair now a big bush as your treasure trail now, thick brown fur. you take a few moments of pause to look over your larger body finding that most of your body is covered in thick body hair, the skin itself now a much darker leathery hide. what could be construed as fur was now constrained around your legs, hips, and face as the rest of the body tried to keep up with the fine fur coating your body.
you try to walk over to Mark, who was taken to rubbing his member agest the trunk of the tree when your first step, causing you to nearly lose your balance. your feet were finishing their changes, toes fused together as your heels have shifted up your body leaving you on a pair of digitigrade legs. Something was swinging behind your ass, you grab behind you to feel a ropey bull tail had grown in behind you.
"this...this is...great...why was I fighting this change." you though to yourself as you feel two points growing out of your forehead and your nose was darkening when Mark after finishing his orgasum, goes to your bull cock putting it in his mouth, one hand on your fusy shaft and the other grabbing your tail.
You feel the beastly energy focus on your mostly human head, you feel the points burst thought your forehead to become a proper pair of horns, and your teeth flatten as you feel your mouth and nose pull out into a bull snout. Your ears grow longer as they move up your head, your hair thicking to proper fur. finally, your eyes become big black orbs as you climax last of your humanity into Mark's mouth and all over his body.
"yes, you are a big mighty beast, now help me change, let me join the will of the woods" Mark screams as you feel the woods take over your mind as you help mark become....