Can the Dual Wielder feat be used to free a hand for casting somatic spells, while two weapon fighting?

Question

Dual Wielder Says:

You can draw or stow two one-handed weapons when you would normally be able to draw or stow only one.

Use an Object Says:

You normally interact with an object while doing something else, such as when you draw a sword as part of an attack.

Can my lv 6 Bladesong Wizard use two weapon fighting, and Dual Wielder to do the following:

• Take the attack action (using Extra attack), to attack with a Rapier.
• Sheath the weapon as part of the Dual Wielder feat.
• Cast a cantrip with a somatic component with his free hand.
• Use a bonus action to attack with his whip.
• Draw his rapier as the second part of the dual wielder feat.

RAW will this combat sequence work?

Answer 1

Yes

At least by the rules.

The rules for manipulating objects come under:

Other Activity on Your Turn

Your turn can include a variety of flourishes that require neither your action nor your move.

You can communicate however you are able, through brief utterances and gestures, as you take your turn.

You can also interact with one object or feature of the environment for free, during either your move or your action. For example, you could open a door during your move as you stride toward a foe, or you could draw your weapon as part of the same action you use to attack.

If you want to interact with a second object, you need to use your action. Some magic items and other special objects always require an action to use, as stated in their descriptions.

The rules for interacting with objects are limited to one object without using your action. As you are drawing and sheathing the same sword, the rules as written do not prevent you from doing it.

The fact that you are sheathing the sword at a different time than drawing it are not covered by the D&D rules as being important.

There is no second object here. The object interaction rules talk about how many objects you can interact with, not when you can interact with the object (other than restricting it to be during your action or move).

However

It is a common interpretation that the "one object" restriction actually means "one object interaction", not "you can interact with one object".

This is such a common interpretation, you are going to have people say it to you as gospel.

This relies on reading "interact" as a description of a singular discrete event, not as a description of your relationship with the object during the action or move.

So you should talk to your DM.

Answer 2

No, it won't.

If you're sticking to the rules as written, then this sequence runs afoul of the Other Activity On Your Turn rule:

You can also interact with one object or feature of the environment for free, during either your move or your action. For example, you could open a door during your move as you stride toward a foe, or you could draw your weapon as part of the same action you use to attack.

If you want to interact with a second object, you need to use your action.

You can't stow your weapon and then re-draw it in the same turn using free interactions because that's two interactions, and the second one would require using an action.

The only thing Dual Wielder changes is when you draw/sheathe one weapon, you can do the same with a second weapon at the same time, which isn't what you're trying to do here.

Answer 3

No…

As mentioned in other answers, the clear intent of the feat is to improve the single free object interaction you get per turn so that you can sheath or draw two weapons at once - not so that you can both sheath and draw a single weapon in the same turn, effectively getting a second object interaction for free.

…but you probably don’t need it to.

You only need to stow one of your two weapons to allow for the somatic component of your Bladesong cantrip, so you can effectively attack twice and cast the spell each turn, even without the Dual Wielder feat. Though this does depend on your table’s ruling on off-hand attacks, and will require you to alternate the order of your attacks.

On your first turn, you can attack with your rapier and stow it as part of the Attack action, freeing that hand to cast your cantrip as your Bladesong Extra Attack. You can then attack with your whip as a bonus action off-hand attack.

On your next turn, just reverse the order: use the Attack action, cast your cantrip, then draw your rapier and use it for your Extra Attack before using your bonus action to make the offhand attack.

Then you can just go back to the first scenario and keep doing this every two turns.

The reason I say “probably” is the way the Two-Weapon Fighting rules work. The relevant rule is:

When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand.

A very strict reading of this rule might be that you need to be holding the “different light melee weapon” in the other hand while making the first attack, which would rule out casting the spell in between.

On the other hand, the rules don’t specify that your bonus action attack can’t be made in between your attacks when you have Extra Attack, so if your table allows it, just attack with the rapier, attack with the whip, stow the rapier as part of the Attack action you’re in the middle of, and then cast your cantrip.

Answer 4

No.

You can draw or stow two one-handed weapons when you would normally be able to draw or stow only one.

Stowing a weapon, doing some stuff, and then later drawing it is not drawing or stowing two one-handed weapons when you would normally draw or stow one. It's doing so at separate times. A simple english reading of the text does not allow for this interpretation.

DnD 5e also fairly consistently improves on some ability or action rather than granting you additional actions as some previous editions of DnD did. Extra Attack does not grant you an additional Action, it lets you attack twice as a single action etc. Many other abilities are more explicit about this than Dual Wielder, but I am only aware of very few exceptions to this general tendency, making it far less likely that the intent of Dual Wielder is to give you two object interactions per turn if both are spent drawing/stowing weapons, and rather that it is intended to allow you to draw or stow 2 weapons whenever you would normally draw or stow a single weapon (to enable a dual wielder to prepare themselves for battle without needing to use their entire turn to do so).