TakeItPairs

The mod adds a cooperative rule in which a rider is carried by the player who is clicking. Only the rider's view and position follow the other player, and the rider can ride other ridable objects while being carried. Riding players keep their seeing yaw in step with the ridden player, and the mining speed debuff that normally applies to a rider is switched off. The ridden player's collision box is ignored, so the pair can move through tight spaces together.

Two people can also use the mod to handle needs that one person alone cannot reach. The rider can be handed a food or drink item by the other player, and a bed spawnpoint set by one player is synced within 6 blocks of the other. The last time each player slept is synced as well, which helps a pair keep their progress aligned. TakeItPairs is a Fabric mod that lets two players share a single set of controls, with one player steering and the other handling movement, so that the pair can keep progressing together.

TakeItPairs is published for Fabric only, on Minecraft 1.21. It needs Cloth Config API and Fabric API, and Mod Menu is optional for its settings screen. The code is under the MIT License and is open source, and the mod runs on client and server, so both the server and every player need it.