At very low speeds, such as in a tight parking-lot turn, how does steering differ from countersteering at higher speeds?

At very low speeds — tight U-turns, parking-lot maneuvers — the rider steers the handlebars directly in the direction of the turn rather than countersteering, because there isn't enough speed to use lean for turning. Smooth, slow-speed control comes from balancing the clutch's friction zone (partial engagement) against a little rear brake and throttle to keep the bike stable, while looking through the turn and shifting body weight to help balance. This is a distinct skill from the countersteering used at road speeds. Practicing slow-speed control builds the balance and clutch control needed for tight maneuvers.