1. Enter a Crouch
2. Start Walking Forward using the Double Tap or just single.
3. Turn using the mouse and let go of the walk button and you will keep walking forward. ( I'm not sure what rate of degree turn is required but I did this alot when walking into buildings and turning to close the door.)
4. Character should keep moving until you straighten out of the turn and then they will stop. Theoretically you could keep moving in a continuous circle.