diff --git a/src/ethopy/behaviors/multi_port.py b/src/ethopy/behaviors/multi_port.py
index 9940252..f91179d 100755
--- a/src/ethopy/behaviors/multi_port.py
+++ b/src/ethopy/behaviors/multi_port.py
@@ -85,7 +85,8 @@ def reward(self, tmst=0):
             tmst = 0
         # check that the last licked port is also a reward port
         licked_port = self.is_licking(since=tmst, reward=True)
-        if licked_port == self.curr_cond["reward_port"]:
+        rewarded_port = self.curr_cond["reward_port"]
+        if licked_port and (rewarded_port == -1 or licked_port == rewarded_port):
             self.interface.give_liquid(licked_port)
             self.log_reward(self.reward_amount[self.licked_port])
             self.update_history(self.response.port, self.reward_amount[self.licked_port])