Co-op Portals
To do that both you and your friend need to:
– Be subscribed to this mod;
– Be friends on steam;
– Be in the game playing (not just in the main menu).
Then one of you makes a Co-op Portal card (3 stone + 1 Flint), links it to the friend, and just drops cards onto the portal.
Portal works both ways so you both can exchange cards.
Also, you can drop the portal onto a card to send it. And yes, it works on hostile creatures too.
If the portal is gray – it’s not activated. That means the other person isn’t in the game or hasn’t opened up a save yet.
When a friend opens up a portal to you a dimensional slit will spawn on your board.
It’s an unstable gateway. You can’t move it and it’ll disappear once your friend logs off.
Craft a portal and link it to the friend to establish a stronger link.
If your friend opens a portal to you without your consent you can just disable dimensional slits.
To do that go to the main menu -> Mods -> Co-op Portals -> and set "allow slits" to off.
This way your friend would be able to send you cards only if you made and linked a portal to them.
Have fun!