lol, the author just controls everything to have her accidentally raped @_@ Random switch, random slide, perfect placement, random bird for thrusting, the whole 9 yards
Let's be real, you can't accidentally insert it there especially in that situation. You need a bit of effort to put it inside. At most, your penis would just miss and curve.
Questioning manga logic would require you to wonder how the hell her skin wasn't ripped to shreds by bird claws yanking on her so hard that it moved her body in a piston motion.