I searched for the poem after watching the episode too. I think it's called "The Beggar Woman" by William King, but I am not certain:
> The Beggar Woman
> by William King
> A gentleman in hunting rode astray,
> More out of choice than that he lost his way.
> He let his company the hare pursue,
> For he himself had other game in view:
> A beggar by her trade; yet not so mean
> But that her cheeks were fresh and linen clean.
> " Mistress," quoth he, " and what if we two should
> Retire a little way into the wood?"
> She needed not much courtship to be kind,
> He ambles on before, she trots behind;
> For little Bobby, to her shoulders bound,
> Hinders the gentle dame from ridding ground.
> He often asked her to expose, but she
> Still feared the coming of his company.
> Says she, " I know an unfrequented place,
> To the left hand, where we our time may pass,
> And the meanwhile your horse may find some grass."
> Thither they come, and both the horse secure;
> Then thinks the squire, I have the matter sure.
> She's asked to sit, but then excuse is made:
> " Sitting," says she, " 's not usual in my trade;
> Should you be rude, and then should throw me down,
> I might perhaps break more backs than my own."
> He smiling cries, " Come, I'll the knot untie,
> And, if you mean the child's, we'll lay it by."
> Says she, " That can't be done, for then 'twill cry.
> I'd not have us, but chiefly for your sake,
> Discovered by the hideous noise 'twould make.
> Use is another nature and 'twould lack,
> More than the breast, its custom to the back."
> " Then," says the gentleman, " I should be loth
> To come so far and disoblige you both:
> Were the child tied to me, d'ye think 'twould do?"
> " Mighty well, sir! Oh, Lord! if tied to you!"
> With speed incredible to work she goes,
> And from her shoulders soon the burthen throws;
> Then mounts the infant with a gentle toss
> Upon her generous friend, and, like a cross,
> The sheet she with a dextrous motion winds,
> Till a firm knot the wand'ring fabric binds.
> The gentleman had scarce got time to know
> What she was doing; she, about to go,
> Cries, " Sir, goodbye; ben't angry that we part,
> I trust the child to ye with all my heart:
> But, ere you get another, 'ti'n't amiss
> To try a year or two how you'll keep this."