Air straws help you pinpoint what you're spraying from a can. It can be air, a lubricant or paint. We've got tips on what to do if you lose that straw, but a drinking straw attached to the can helps prevent you from losing it in the first place.
Family Handyman reader Jim Kucharik attaches a drinking straw to a can with glue, but you could use duct tape. The air straw goes inside the larger drinking straw. Now you've got someplace to put the air straw when you're done.