im a silly goose (#21005)

code/game/objects/items/weapons/implants/implant_storage.dm

@@ -5,6 +5,7 @@
 	max_combined_w_class = WEIGHT_CLASS_GIGANTIC
 	w_class = WEIGHT_CLASS_BULKY
 	cant_hold = list(/obj/item/disk/nuclear)
+	w_class_override = list(/obj/item/storage/belt)
 	silent = TRUE
 
 /obj/item/implant/storage

code/game/objects/items/weapons/storage/belt.dm

@@ -31,7 +31,7 @@
 	update_weight()
 
 /obj/item/storage/belt/can_be_inserted(obj/item/I, stop_messages = FALSE)
-	if(isstorage(loc) && !istype(loc, /obj/item/storage/backpack/holding) && !storable)
+	if(isstorage(loc) && !istype(loc, /obj/item/storage/backpack/holding) && !istype(loc, /obj/item/storage/hidden/implant) && !storable)
 		to_chat(usr, "<span class='warning'>You can't seem to fit [I] into [src].</span>")
 		return FALSE
 	. = ..()