Known by many names, "over the shoulder", "pilot/copilot", "side by side", "on the job", on-premises training is at the client location with client EDI/integration software, in the client IT environment, with the client/partner implementation requirements, and with at least one if not many client resources.
The result of this approach is a staff/consultant experience that goes from integration spec analysis, to development/testing, to production implementation. All this unfolds in a custom manner with staff participation in a real test/production environment, with a real instance of the client ERP system, and with actual partner integration opportunities.
Other than live implementations engagement goals vary based on budget and include: trained staff, documented systems, knowledge transfer, and organizational self sufficiency.
With all of the benefits, no wonder this training approach has been so popular for so long.