Irahl is unfortunately not braced at all for the sharp blow that returns his own not-very-nice strike, (which is weird, considering how much control he's still sure he has over this situation,) so there is a good second or two afterward that is spent only on struggling to reorient himself.

The fact that Vincent shoves down on his injured shoulder goes entirely unnoticed. However, as his ears ring and vision swims, he is at least vaguely aware of Vincent getting too close... and he's already beginning to shove very clumsily at his friend's shoulder when he suddenly realizes exactly how close he's getting. He fails to catch the reactionary way his claws curl and dig in a little when it registers.

In the very back of his mind, more little bells of familiarity are beginning to ring.

Vincent's face is too close to properly headbutt. So, unintentionally following a few more of the steps they'd danced through once upon a time, he tries to shove Vincent's face away with the side of his of his own to get him away from the touchy vicinity of his own neck.

It would probably be easier to push Vincent away if he would also let go of the arm he still has locked up, but that's too many limbs for him to keep track of at the moment.