I was looking at the Virginia Secession Convention journals, and this little item caught my eye:
An act providing for the voluntary enslavement of George, Shed, Sam and Sukey, persons of color in the county of Buckingham, No. 124.
A little looking around led me to an item in the New York Times from 1856 that sheds a little light on the issue. By Virginia law, freed slaves had to leave the state within one year after manumission. For various reasons, some of them preferred to stay — particularly if they had spouses and children who were still enslaved. The legislature had to act to enslave a free person, so acts such as this were pretty common business. The Virginia Secession Convention was a special session of the legislature, so they dealt with “routine” matters such as this.
There’s an article by Emily West in Slavery and Abolition entitled ‘She is dissatisfied with her present condition’: Requests for Voluntary Enslavement in the Antebellum American South. I don’t have immediate access to the journal, but it looks like an interesting topic.