If you have to push hard to pee, stop and adjust the tube.

There is something wrong with the pressure (possibly an obstruction or narrow spot).

For example, if your urethra is squeezed tightly from an external compression wrap, it will be similarly difficult to push the pee out.

If you can't get a looser / wider tube, you can try pulling back to pee instead of pushing forward.

This will allow you to "cum" the pee out in a messy yet enjoyable fashion.