diff --git a/code/game/objects/effects/map_effects/portal.dm b/code/game/objects/effects/map_effects/portal.dm
index 2331cac8e8..2e3b101d3b 100644
--- a/code/game/objects/effects/map_effects/portal.dm
+++ b/code/game/objects/effects/map_effects/portal.dm
@@ -9,6 +9,11 @@ Portals do have some specific requirements when mapping them in;
 	- There must by one, and only one `/obj/effect/map_effect/portal/master` for each side of a portal.
 	- Both sides need to have matching `portal_id`s in order to link to each other.
 	- Each side must face opposite directions, e.g. if side A faces SOUTH, side B must face NORTH.
+	- Clarification on the above - you will be moved in the direction that the portal faces.
+	  If Side A faces south, you will be moved south. Dirs are 1/2/4/8, 1: NORTH, 2: SOUTH, 4: EAST, 8: WEST.
+	  To further explain: If your cave entrance is on the NORTH side of the map on ENTRY side, and SOUTH side on EXIT side:
+	  You will need to set the ENTRY side's dir to 2, IE SOUTH, as that's the direction you will moving coming FROM the EXIT side.
+	  IE: Directions should be set based on the direction of travel.
 	- Each side must have the same orientation, e.g. horizontal on both sides, or vertical on both sides.
 	- Portals can be made to be longer than 1x1 with `/obj/effect/map_effect/portal/line`s,
 	  but both sides must have the same length.