Write a verse, one line per bar. Rhymes light up as you type, the margin letters the scheme, and play puts your syllables on a beat. Each syllable plays its vowel as a note, so a rhyme comes back as the same note and you can hear your scheme.
Your lyrics stay in this page. The copy link button puts them after the # in the link, a part browsers never send to a server, so only people you give the link can read them.