Besides Session IDs and Session Tickets[1] which already exist in the TLS protocol. He could be referring to the Token Binding Protocol Draft[2] which, quoting from it's summary, "allows client/server applications to create long-lived, uniquely identifiable TLS bindings spanning multiple TLS sessions and connections".

[1] https://en.wikipedia.org/wiki/Transport_Layer_Security#Resum...

[2] https://tools.ietf.org/html/draft-ietf-tokbind-protocol-01