... in Arthur Waley's 1921 translation!

Dance, dance, Mr. Snail!
If you won't I shall leave you
For the little horse,
For the little ox
To tread under his hoof,
To trample to bits.
But if quite prettily
You dance your dance,
To a garden of flowers
I will carry you to play.

舞へ舞へ蝸牛。舞はぬものならば、
馬の子や牛の子に蹴させてん、
踏みわらせてん。
まことに美しく舞うたらば、
華の園まで遊ばせん。

I love the very English translation of makoto ni ("verily", "in truth") as "quite." I seem to recall a Pillow Book translation of similar vintage that used "rather nice" for ito okashi.

Yamaguchi Misa 山口美佐's Ryōjin hishō page observes that the message of this song (i.e. "if you don't do what I want, I'll kill you") really brings out the hardass (強硬) nature of the times (i.e. the crumbling, violent end of the Heian golden [for nobles] age). Yamaguchi also mentions a derivative poem by Jakuren 寂蓮:

牛の子に踏ますな庭のかたつむり角のあるとて身をなたのみそ

Let not the garden snail be trampled by the little ox! Horns he may have, but he is not so strong.

(Other versions are addressed to the snail himself.)

Here's one more Ryōjin hishō poem for good measure:

頭に遊ぶは頭虱、頂のくぼをぞ極めて食ふ、櫛の歯より天降る、麻小笥の蓋にて命終はる

On my head sport head-lice, the nape of my neck they ever bite, they descend from the teeth of the comb as if from heaven, and on the barrel's lid do their lives end.

Momoyama Harue 桃山晴衣 has recorded versions of these songs (with music by herself, of course, since none has survived). You can hear her version of the head-lice song as part of this medley.

For good measure, here's another video of Momoyama playing a reconstruction of the oldest known shamisen tune, "Renbo nagashi" (Roughly and idiomatically, "Lookin' for love blues," although there is debate over what "renbo" really means... for example, many in the shakuhachi community feel that "renbo" 恋慕 in the "love" sense must be derived from their "reibo" 鈴慕 "yearning for the bell" rather than the other way around, if the two are related at all.)