Pitot Joiner tube help needed

[WingedFrog]

I need to slide about 2" of each Pitot tube lines into the 4" pitot joiner tube. Although I used VANs tip of dipping the joiner tube into hot water, I am unable to slide more than 1" in each end. There is no grip on these tubes that collapse if they are squeezed. Seems to me that some lubrication would help but I don't want to use something that would hurt the plastic tubes or create leaks. Any tip?
Thanks

 

[lewy]

Pitot tube

Hello, I think we used a hair dryer(blower).