This is a traditional Scottish saying in rural Stirlingshire which means as it sounds in English 'May your turtles have 3 heads'. It is a phrase typically used by those who aim to wish a person a deep sleep. It is unclear of the origins of the phrase, especially as there are no wild turtles in Scotland and Stirlingshire has no coast, however it may have originated when Scotland was a driving force of the commonwealth.
"I'm aff tae bed now, cheery ho"
"Aright then, May all yer turles hae' three heids"
"Thanks pal, and yae tae"
May all yer turtles hae' three heids