Endorsement for spin training: FAR § 61.183(i)(1) and (2)
I have given Mr./Ms. flight training in stall awareness, spin entry,
spins, and spin recovery techniques in an (airplane/glider) (state
which category), and he/she has demonstrated instructional
competency in those maneuvers as required by CFR
61.183(i)(1) and (2).
If you read the endorsement, it states that the pilot
demonstrated instructional competency in spins. Not that
we went out and did two or three spins.
All CFI applicants are required to have a spin endorsement.