system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 How do slipstreams work?

What is a slipstream and how do they work? Is there an ideal distance behind another car you should stay to get the maximum benefits? Is there a distance where it actually becomes a hinderance? If there is a crosswind does it destroy any chances of a slipstream?
gpt
When something moves through air, it leaves an empty space behind it. New air moves to fill that space, which is the phenomenon you're calling a slipstream.

If it's a very large object moving quickly, like an 18 wheeler going down the highway, there can be a lot of air moving in behind it, and if you're close enough, you can be pulled along with the air.

The ideal distance will vary depending on the size and speed involved, but it's generally a bad idea because you need to be an unsafe distance from them. You're basically tailgating them.

A cross wind would have an effect, because the point of lowest air pressure behind the truck would move, but again, not really worth considering because you'd have to be right up their ass.