First you need a pet which is large enough to ride, not humanoid and has a solid physical form (e.g. not amorphous like a pudding or whirly like a vortex). You must also be in a humanoid form and not too big or small to fit on a saddle.
Next you need to saddle the pet by applying the saddle to it - you need at least one free hand for this. It is possible to saddle a non-tame monster, but this is more difficult than saddling a pet, and you will not be permitted to ride the monster until it is tamed.
Now mount the steed with the #ride command. Unless you are a Knight, this will make it less tame and may untame it. If any of the following conditions hold, you simply won't be able to ride for obvious reasons:
- You are already riding.
- You are hallucinating.
- Your legs are wounded.
- You are Stressed or worse.
- You are blind and not telepathic.
- You are punished.
- You or your steed are trapped.
- You are levitating and cannot come down at will.
- You are wearing rusty or corroded body armour.
If any of the following hold, you will slip while trying to get on the steed, and will lose some hit points. This can also happen by chance when you're not impaired in any way.
- You are confused.
- You are fumbling.
- You have slippery fingers.
- Your steed's saddle is cursed.
To stop riding, do the #ride -command again.
Pros and cons
While riding, your carrying capacity will be set to maximum. Your steed will be more passive than when not ridden - it will not pick up items and will not spontaneously attack monsters. Instead, monsters have a chance of attacking your steed instead of you: when they do, then your steed will counterattack. You will move at the speed of your steed (a horse is as fast as a character wearing speed boots, and a warhorse is even faster). Polearms can be used effectively at close range while riding.
On the other hand, you cannot eat food (notably corpses) off the ground while riding, and can only pick items up if you have at least Basic riding skill. Pets are not reluctant to be ridden over cursed items. If you ride a non-flying steed downstairs while burdened, you will fall off and injure both legs. Also, you should not use Conflict while riding: your steed can throw you off. However, a ki-rin's high magic resistance and experience level will make it always resist (unless you level drain it below level 15).
Possible choices of steed
- Horse - grows stronger and faster, and is easy to tame, but is difficult to keep fed as it is herbivorous.
- Unicorn - does good damage and (like the warhorse) can have a speed of 32 when zapped by speed monster.
- Dragon - can fly, is strong, is carnivorous (so easy to keep fed), and can be acquired by laying an egg, but is slow. Also, a dragon will not use its breath weapon while you are riding it.
- Ki-rin - fast, can fly, and does not eat (be aware that this means that it is more likely to go wild) but is difficult to tame and also somewhat rare.
- Centaur - slightly slower than warhorses and unicorns, but is omnivorous, and can equip a shield of reflection and a weapon.
- All quadrupeds - Leocrotta in particular due to its speed (18, same as ki-rin).
- In SLASH'EM there is also Pegasus, who is as fast as a warhorse, stronger, can fly, and does not eat.
In general, all quadrupeds, unicorns (which includes horses), angels, centaurs, dragons, and jabberwocks are ridable. However, the test is limited to those that are of size medium or larger, not humanoid (except for centaurs), not amorphous, not non-corporeal, not "whirly", and the creature must be solid. Foocubi are notable for giving a funny message if you attempt to saddle one ("Shame on you!")
Your steed will be subject to the traps that you ride through. This means that if you ride into a pit, your steed will be damaged by the fall. If you ride into a polymorph trap, your steed will polymorph - most likely into something that can't carry you. When you hit the ground, you will polymorph too. However, tameness is not decreased by riding into traps - even known traps, unlike other methods of leading a pet into a trap.
Your magic resistance will protect the steed as well. A polymorph trap will only make you feel "momentarily different" if ridden into while wearing a cloak of magic resistance. If you're worried about losing that powerful (and ridable) pet of yours to a random trap, riding might be just the thing for you. Note that amulets of unchanging will also prevent both you and your steed from polymorphing, but this obviously won't protect from other traps. Too bad you can't saddle an Archon.
It is possible to mount a steed if you are levitating "at will", as from quaffing a blessed potion of levitation, casting the levitation spell at skilled or expert, or invoking The Heart of Ahriman. ("<Steed's name> magically floats up!"). Only invoking The Heart of Ahriman will levitate the steed along with you, however -- if you levitate via the potion or the spell while riding, you will find that you "cannot stay on" your steed, will have to remount if possible to levitate your steed.
Monsters will attack your steed. If you have a stethoscope, you can determine the health of your mount by using ">" as the direction to apply it. Be sure to run away if your steed is in trouble.
The riding skill
Many classes have the riding skill. It takes 100 steps while riding to exercise the riding skill. To go from unskilled to basic, it will take 2000 steps while riding. Note that this may be fewer than 2000 turns since most ridable monsters are faster than the turn rate. For those 2000 steps, you won't be able to pick things up off the ground, which can be frustrating.
Being unskilled at riding hurts your chances to mount the pet and doesn't allow you to pick things up from the floor. You also can't set traps, dip things in pools (unless you're riding a swimming steed), and decreases your chance to hit (-2 for unskilled, -1 for basic, and always an additional -2 when #twoweaponing).
Having a skill greater than Basic increases your chance to mount. It also removes the to-hit penalty. With these relatively minor benefits to increased Riding skill, it may be better to spend your skill slots elsewhere.