Sit

The #sit extended command makes your character to sit down; this can have different effects (and messages) depending on what you're sitting on.

Sitting on a trap while you're trapped in it abuses wisdom, and for some traps, makes you stuck in it longer, pool will rust your armor. Probably the most used feature is sitting on a throne.

You can also lay eggs by sitting if you've polymorphed into female oviparous monster.

Tactics

If you were needing an emergency getaway method such as a teleportation trap or a trap door and you managed to escape it when entered the square, you can just #sit as it will activate the trap.

There's a bug according to this, for ex. a gnome had died to a pit and you want to loot the gnome, but you escape when you try to enter the pit. Trying to #sit gives you a message about the uncomfortance of sitting on the gnome corpse and you won't fall to the pit.