Where do you put the eucalyptus oil in the humidifier?

This may sound silly but I am just not sure where to put it! Do I put the drops right in the water?





My 7 month is really congested and has a bad cough. We are going to the doctor tomorrow but I just want to ease him a little bit through the night.Where do you put the eucalyptus oil in the humidifier?
yeah u can put them in the water or most humidifiers should have like a little half circle looking thing right in front of where the steam comes out put it in there too. but putting it in the water does the same thing you'll still get the same smell coming out