Little Musgrave was one of the most widely printed and popular ballads of the 17thc. It was first registered as far as I can make out in 1630 to Francis Coles but Pepys has a version printed by Henry Gosson who was active 1601 to 1641. It was also registered in 1656, 1658 and 1675.

The earliest version I have access to (Gosson) has 'lay on his brest and swumme'. Wit Restored, a more upmarket songster type of 1658 has 'laid him down to swimme'. All of the other copies I have from about 1670 onwards and there are lots going right into the 18thc have 'bent his breast.....' You can see lots of copies of these on the Bodleian site, Douce, Wood, Firth etc. There's also a copy that has just come online on the English Broadside Ballad Archive site in the Crawford Collection. In fact there will also be various Pepys and Roxburghe copies on this same site.

The ballad was so popular that I wouldn't be surprised to learn that other ballads that have adopted the phrase took it from Musgrave.