2T4U/Jack/nature trail/“fort”/Grab her head and shove your dick in her mouth
All right, this is just too much for your already sexually stimulated brain. You have been on edge all morning, and now the prospect of just fucking the hell out of this girl you randomly met on the trail is filling your head and dominating your thinking. That's it, you're going for it.
In a few steps, you come around to stand in front of her. In her sitting position, this brings your cock to just above her forehead. She jumps in surprise as you come into her view, and then she begins looking up at you with wide-eyed shock. In the moment before she can make a sound, you are quick to grab the back of her head in both hands and thrust your cock at her slack-jawed mouth. Rather than close her lips, she actually seems to open a little as you press your glans against her lips. In a second, you have seized this opportunity and pressed past her defenseless mouth and have the first 2 inches of your cock completely inside of her lips. It is only then she seems to start resisting.
“MMMM!! Mmmm.. mmm...” she begins protesting past your shaft that is filling her mouth. Despite her resistance though, her lips stay closed tightly around you. She does, however, begin pushing hard with her hands against your hips and trying to press her head back against the thick stock of the large overgrown tree-like bush that makes up “the fort.”