I've had this same issue with SoundHound, as they've advertised this same feature for a while now. The problem is, sometimes I only have half of the chorus stuck in my head and I want to hear the rest but I don't remember it.

I just tried it with a guitar driven song I've had stuck in my head lately. I only remember about 5 seconds of the chorus, but it's what I would consider a fairly memorable and catchy hook.