You can carefully work on the cable sheath with linesman pliers to spread the coils apart, giving you a moderate amount of friction. Employ a moderate amount of mash with the pliers. If you need more friction, move the the next coil and give it another mash.
Putting a slight kink it the cable wire will also work fine on a throttle cable without worry.
I would not do that on a loose choke cable since it may fail when you push it back in.
Carl