A haircut is an ordinary, almost forgettable moment, but this tiny poem follows it somewhere unexpected. The speaker's gray hair is cut, falls away, and is swept down a drain. From there, the poem imagines it travelling through the sewers and eventually out to sea. The dash after "cut" works like a small pause, a snip, before the thought carries on.
What the speaker feels is quietly open to interpretation. There's a hint of wry humor in picturing something so personal making such a long, grubby voyage. But the word "gray" also points to age, so the hair leaving feels like a small piece of the speaker's years drifting off. The phrase "going to sea" sounds adventurous, even a little grand, which sits oddly against the plain, unglamorous sewers.
The mood is light, reflective, and gently melancholy. The poem shifts from a tiny, everyday act to something vast, and it suggests that even our discarded bits keep moving through the world after we're done with them.