## RAW, it's valid if the ranger is strong enough : The push, drag or lift rule.

Thanks to the comments under this answer, I realized that the Grapple *can* be used but doesn't really take into account the fact that the target is willing. Then, I thought: "The Warlock is already as fast as an anchor, what if we stop considering them as a creature and just as loot to transport?". Here comes the "[Push, drag or lift rule][1]" :

> You can push, drag, or lift a weight in pounds up to twice your carrying capacity (or 30 times your Strength score). While pushing or dragging weight in excess of your carrying capacity, your speed drops to 5 feet.

This allows the floating warlock to be pushed around by another character, as long as they are strong enough!

##But I think your first ruling was totally okay

Even if it wasn't RAW, rule of cool totally applies here, I think your ruling was good. This was a great idea and you rolled with it. Great job.


[1]: https://www.dndbeyond.com/sources/basic-rules/using-ability-scores