This video shows how to work a C3F cable without using a cable needle.

To work a C3F left leaning cable without a cable needle, with RS facing and working behind the stitches, knit into the back of the 3rd stitch on the left hand needle; then, without slipping this stitch off the needle and now working in front of the stitches, knit the 1st and 2nd stitches on the left hand needle; with the new loops now on the right hand needle, slip the worked 3rd stitch off the left hand needle.