Can you throw yourself off your mount?

Question

The mounted combat rules for normal ("safe") dismounting are as follows:

Once during your move, you can [...] dismount. Doing so costs an amount of movement equal to half your speed.

Some external factors might forcefully dismount you:

If an effect moves your mount against its will while you're on it, you must succeed on a DC 10 Dexterity saving throw or fall off the mount, landing prone in a space within 5 feet of it. If you're knocked prone while mounted, you must make the same saving throw. If your mount is knocked prone, you can use your reaction to dismount it as it falls and land on your feet. Otherwise, you are dismounted and fall prone in a space within 5 feet it.

But what if you don't want to "safely" dismount (landing up), and instead, throw yourself off your mount, landing prone? Can you even do such a thing - either via the above Dexterity saving throw (where failure is the desired outcome), or through an Acrobatics/Athletics/Animal Handling check, etc.? More so, would it cause damage to brutally throw yourself off a moving mount?

The purpose of this (as I'm sure you will ask!) is for someone with the Athlete feat (or 6 levels in Way of the Drunken Master Monk) to spend less movement on dismounting (i.e. less than an amount equal to half their speed) by throwing themselves off, landing prone, and quickly getting back up.

Answer 1

Some forcible dismounting conditions might be triggered by voluntarily dropping prone

One of the triggers for getting forcibly dismounted is being "knocked prone while mounted". Since you can voluntarily drop prone on your turn, this should allow you to activate this trigger. You will then need to convince your DM to allow you to voluntarily fail the dexterity saving throw, or just hope you roll low on it.

Similarly, if your mount is knocked prone, you are forcibly dismounted. Hence, you could have your mount voluntarily drop prone to trigger this dismounting, and then stand up using 5 feet of your movement. This is preferable if your DM won't let you voluntarily fail the saving throw mentioned above, although it potentially limits the mobility of your mount and puts it in danger if it ends its turn prone. (Maybe you should consider the Athlete feat for your mount!)

"Knocked prone" vs. "dropping prone"

Note that both of these options assume that there is no functional difference between dropping prone and being knocked prone, since the conditions for forcible dismounting specify being knocked prone. The rules are not clear on whether there is meant to be a distinction or not. If your DM decides that voluntarily dropping prone is not equivalent, then the above will not work.

Personally, I would rule that there is no difference: that is, being knocked prone and dropping prone are just 2 different ways of imposing the prone condition on a creature. But this is certainly not the only reasonable ruling.

For a home game, consider cutting out the middleman

Since you asked about this because of the potential interaction with the Athlete feat, I would suggest that if you're planning on using this in a home game, you should consider just adding an extra feature to the feat that allows dismounting safely using 5 feet of movement instead of half your movement (or asking your DM to do so). That will remove the need for shenanigans involving dropping prone as an "intermediate" state for quick dismounting.

Answer 2

Yes although I don't believe there are specific rules for it

1. The DM describes the environment.
2. The player describes what they want to do.
3. The DM narrates the results of the adventurers' actions.

As a player you can tell the DM you are going to throw yourself off the mount instead of dismounting. It is then up to them to decide if / what they want you to roll and if you'll take damage.

As far as I know there aren't any pre-written rules for the situation you describe so it is up to the DM to decide.

As a DM I would interpret it as the player recklessly throwing themselves off the mount and would ask for a DC 20 Dexterity save to avoid taking damage which I would call 1d6 if the mount were stationary and 2d6 if moving (depending on movement from last turn if no movement has be used this turn.) I might also adjust this depending on the terrain for example adding 1d6 on rocky terrain or treating the d6's as d4's on sand.