DC motor extruder control

Hi

I have a problem and was hoping you could help.

I am building a 3d printer from "junk" .
So far i was able to make the x,y,z axis work , even tested them with a pen n paper since i cant use extrusion wich is where my trouble comes in.

Im using an arduino uno board to control everything and the Teacup Firmware. Its all nice and good until i get to configuring it to use a dc motor extruder.
The reason for the dc motor is i also built the hot end myself and the extruder using gasstove nozzles and such. Happy to say it extrudes plastic if i run the motor.

Now if someone could explain to me where and what i should define in the printer.h and board.h files of teacup , or the config tool and how to configure / determine the pin i need to use to send controls.

And before someone says "just use a stepper" thats a no no . I have to use a dc motor beacause of a future mod i might do to it.

Ty in advance and sorry if i didnt post in the right forum or if my post is in some way bad.