EFRPs cover exchange for physical, exchange for risk (futures against a swap) and exchange of options for options. All require a genuine, matching related position — the cash or swap leg cannot be a fiction invented to justify an off-screen futures print.
Exchanges police this hard, because a fake EFRP is just a way to move futures positions between accounts at arbitrary prices. Fines for non-bona-fide EFRPs are routine in CME disciplinary notices.
Example: a bank holding a crude swap with a client transfers the risk into futures via an EFR, receiving futures and cancelling the swap at an agreed differential.
Related: exchange-for-physical, block-trade, market-manipulation, clearing-house, cftc