Well on the same note of instinct, its the most primal built instinct to protect your young, however in frenzy, you'd murder them without a thought as well. Aside from the instinct of "Die die die, everything must die!", there's not a lot going on. By that logic, someone who trains constantly with their guns, to the point where wielding them becomes instinct, ((and it does, fyi)) then wouldn't that mean, we'd have to include ranged weapons as well, to be able to be fired off during a frenzy?
You'd still have a spiritual link the the gun, and it would be your instinct to use it, ergo, you can frenzy with guns.
If your weapon is sheathed or holstered, it would be your instinct to draw it in order to use it. Drawing a weapon is the most basic of instinctual maneuvers.
If you were disarmed in combat, your instinct tells you to recover your spiritually attuned weapon.
If you are no longer able to activate fetish weapons, you will have to note how your weapon works if it were mundane with less damage, or a loss of traits.
If you train long and hard to where using your fetish's property is instinct while wielding the weapon, you would still maintain the ability to activate it.
((These are just premises that will need to be answered if it comes up))
Which is why I think, you'd just drop them and turn into a whirring ball of fur, claws and teeth, despite the fact that it isn't advantageous at all.
If you drop it you drop it.