How to get flex PVC to go straight

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Odd question perhaps.. but in the smaller sizes <1" it can bend and flex pretty easy.. now I have to run two 1-1/2" lines on my herbie under the tank under the stand, through the wall and into the sump.. a total journey of about 5 ft.. now the problem is that the bloody pipe is curled up like it was on the reel.. any suggestions to make it a little more pliable?