What does gay EC mean?

Enforced Chastity, mainly in reference to BDSM. This is when the submissive is denied the ability to have an orgasm.

Definition

Enforced Chastity, mainly in reference to BDSM. This is when the submissive is denied the ability to have an orgasm, over a prolonged period of time. Used as a means of asserting the dominance of one over the other.