Can I do a Performance during combat? Does it cost an action?

Question

I am playing a Drunken Master monk and trying to come up with creative and fun ways to use their abilities.

One of the features every guide says is useless is the proficiency in Performance, so I have been thinking of how I could use that in combat.

I've come up with the following tactic, starting from melee range:

• Action: Attack and Extra Attack
• Bonus Action: Flurry of Blows and Disengage (Disengage is free with Drunken Technique)
• Movement: Run away in the opposite direction of the party and knock myself prone
• Performance: Snore loudly to convince enemies I have fallen asleep

My question is: can I do the last step, the Performance, for free, just like speaking?

I was hoping it could draw enemies away from my mostly squishy party: "this guy just punched us a bunch, tried to run away, fell drunk on his face and is now unconscious, let's get him", or at least confuse them in some way.

Answer 1

What this requires is up to your DM

Most importantly, you don't get to decide you want to make a Performance skill check. You can narrate that you want to drop down and simulate snoring, and then your DM decides, if that just works, or if you would need a skill check for it, and if so, if it requries Deception or Performance.

This goes back to the fundamental loop of the game (p. 6 PHB):

1. The DM describes the environment
2. The players describe what they want to do.
3. The DM narrates the results of the adventurers’ actions.

Because of this, your DM will have to decide if you need to make a check, or not, and if so what kind of check.

General consensus is that there is no rule that every use of a skill requires an action in combat, as explored in depth in: In combat, do all skill checks require an action to perform? and also here: Do ability checks in combat require an action?

Most DMs require an action for skill checks in combat, but the choice is up to the DM. So if they agree that you can try a Performance check, they also need to tell you if that check requires you to use your action.

The text of the rules sometimes uses action in a less formal way than the defined "your action" for the turn in combat. For example, the section "Other Activity on your Turn" (p. 190 PHB) advises you

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.

The inset box "Improvising an Action" (p. 193, PHB) tells you

Your character can do things not covered by the actions in this chapter, such as breaking down doors, intimidating enemies, sensing weaknesses in magical defenses, or calling for a parley with a foe.

So what is calling a parley now? On one hand, the rules tell you it is an improvised action. On the other hand, all you need to call for a parley is to shout "Parlay! Parlay!", a brief utterance if there ever was one, that does not require your action. Because of the ambiguitiy of what is or should be sufficient to affect the action economy among the countless possible things you can try, the DM is called upon to adjudicate.

Answer 2

A strict reading of the rules implies that using a skill requires an entire action.

In the Actions in Combat section of the PHB, we have a list of options to use for an Action (e.g. Attack, Dodge, Hide, et cetera), and we can find the following bit:

When you describe an action not detailed elsewhere in the rules, the DM tells you whether that action is possible and what kind of roll you need to make, if any, to determine success or failure.

Moreover, there is another part of the rules about improvising an action (emphasis mine):

Your character can do things not covered by the actions in this chapter, such as breaking down doors, intimidating enemies, sensing weaknesses in magical defenses, or calling for a parley with a foe. The only limits to the actions you can attempt are your imagination and your character’s ability scores. See the descriptions of the ability scores in chapter 7 for inspiration as you improvise.

When you describe an action not detailed elsewhere in the rules, the DM tells you whether that action is possible and what kind of roll you need to make, if any, to determine success or failure.

For example, the bolded part above implies that you are using the Intimidation skill.

In your case, you are improvising an action not listed in the Combat section of the PHB: using a skill falls in this "improvised action" framework, hence you need to take the entire action to use a skill.

This is confirmed in the Ability Checks section in the PHB (emphases mine):

An ability check tests a character’s or monster’s innate talent and training in an effort to overcome a challenge. The DM calls for an ability check when a character or monster attempts an action (other than an attack) that has a chance of failure. When the outcome is uncertain, the dice determine the results.

There are some classes that are able to use a bonus action to make an action (such as the Rogue's Cunning Action), and the Fighter can take an additional Action on their turn using Action Surge. In the case described, however, the Performance check cannot be done.

Note, however, that the DM should call the type of skill check to be done in order to determine the course of actions (see this answer that covers this aspect). Indeed, in this case the Deception skill is more suitable for what you are trying to accomplish here (credits to Nobody the Hobgoblin that pointed this out in the comments).

The DM has the final word on it.

A DM could rule otherwise and decide that using some skill was free. In some cases, this would ease the game and it does make sense (e.g., during movement you make an Athletics Check for swimming in tumultuous waters, or something similar).

To be honest, in this case as a DM I would be very tempted to allow a player to adopt the strategy described because it is very cool, but allowing it means that all the players should be allowed to make a skill roll for free during their turns, and this could be really game-breaking in some situations (e.g., allowing a character to Hide for free during combat).