On the steering wheel for me always. Zip tie or secure a part of the cable close to switch to the steering wheel and if need be on the dash end as well. The cord will stretch quite a but securing the button end to the wheel will keep the stress off of it. We have three buttons on the dragster wheel as well and those wheels get turned a fair amount driving to and from the lanes and off track. The dragsters cords are secured on both ends my car is only on the wheel, with two cords, one for brake one for the chutes. Been doing it this way for years with zero issue doing it this way