Fast travel after clicking throw on an item/enemy/body, but before selecting a target. Then click on the portrait of a teammate who was a potential target at your character's pre-fast-travel position. Bring anything you can throw anywhere you want.

Companions leave camp at the same time you do, so if you want to yeet using "Leave Camp"(i.e. from a custom location, instead of a fast travel location) your in-camp target needs to be a non-companion follower(Halsin, or something raised by Glut).