See, that's pretty funny, but Vincent can't think of a decent comeback fast enough to keep the joke going. As seconds pass with no retort, he realizes he either has to give up (unacceptable) or so something to heighten the joke so far that Irahl is forced to crack.

So after a moment of almost-stony-faced silence, he slowly pushes himself out of his bedroll and reaches over... To try and casually put his friend in a headlock.

"Where's your neck, you smarmy piece of shit..."

He's doing this all comically slowly, Irahl has plenty of warning in case he hates this--but if allowed, he'll absolutely bodily bully him over and shove him into the ground if he can get away with it.