An onomatopoeia describing brisk little steps or someone trotting along with small, light footsteps (often used for children or small animals).
子猫が部屋をトコトコと歩き回っている。
A kitten is trotting around the room with small, quick steps.
朝、赤ちゃんがトコトコ近づいてきて、笑いかけてくれた。
In the morning, the baby toddled over with small steps and smiled at me.
犬が飼い主のそばをトコトコ歩いた。
The dog trotted beside its owner.