This video shows how to knit a C4B cable without using a cable needle.

To work a C4B right leaning cable without a cable needle, with RS facing and working into the front of the stitches, knit the 3rd and 4th sts on the left hand needle; then, without slipping these stitches off the needle, 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 and 4th stitches off the left hand needle.