Dual Channel Damper rubber plugs

Just did a dual head swap on our JV300 sublimation machine.

The old dampers had rubber plugs in the two forward ports on the top of the damper. I pulled the plugs out of the old dampers and am trying to put it into the new ones but can't seem to get them in. Does anyone have any tips? The little rubber damper plugs were originally inserted with the flared side down.

Thank you in advance!