Don’t. Even if you understand what you’re doing, someone else won’t and your family will die in a house fire.
Male-to-male end cables allow for the two leads of an open male end to make contact with anything conductive (including your flesh, causing some pretty gnarly burns) to complete the circuit and start a fire. No conscionable electrician will make these for you. It is the dumbest solution to any problem you’re looking to solve. Don’t.
Just a reminder coming up on Christmas.
We used one to run power to a garage a couple times per year. It’s relatively safe if you use it right and never have power running through the cord until it’s fully plugged in.
Safe, until someone (accidentally) detaches the wrong end.