expression, godan verb (-ku)
uncoil itself; unwind its coils
Used for a coiled snake or similar creature relaxing its coiled posture. Often appears in descriptions of snakes in nature or figurative contexts.
蛇がゆっくりととぐろを解いて動き出した。
The snake slowly uncoiled itself and started to move.
塒 is a rare kanji for とぐろ; this spelling is seldom used.
蜷局 is an uncommon kanji spelling for とぐろ; mostly seen in literary contexts.
とぐろを巻く means 'to coil up' (as a snake), the opposite action of とぐろを解く.
とぐろ (coil) + を + 解く (untie, undo). The phrase literally means 'to undo the coil'.